java.lang.Object
- com.google.common.net.HttpHeaders

```
@GwtCompatible
public final class HttpHeaders
extends Object
```
Contains constant definitions for the HTTP header field names. See:
Since:

11.0

Author:

Kurt Alfred Kluever

Nested Class Summary

Nested Classes
Modifier and Type Class Description

static class HttpHeaders.ReferrerPolicyValues
Values for the Referrer-Policy header.

Field Summary

Fields
Modifier and Type	Field	Description
`static String`	`ACCEPT`	The HTTP `Accept` header field name.
`static String`	`ACCEPT_CH`	The HTTP `Accept-CH` header field name.
`static String`	`ACCEPT_CHARSET`	The HTTP `Accept-Charset` header field name.
`static String`	`ACCEPT_ENCODING`	The HTTP `Accept-Encoding` header field name.
`static String`	`ACCEPT_LANGUAGE`	The HTTP `Accept-Language` header field name.
`static String`	`ACCEPT_RANGES`	The HTTP `Accept-Ranges` header field name.
`static String`	`ACCESS_CONTROL_ALLOW_CREDENTIALS`	The HTTP `Access-Control-Allow-Credentials` header field name.
`static String`	`ACCESS_CONTROL_ALLOW_HEADERS`	The HTTP `Access-Control-Allow-Headers` header field name.
`static String`	`ACCESS_CONTROL_ALLOW_METHODS`	The HTTP `Access-Control-Allow-Methods` header field name.
`static String`	`ACCESS_CONTROL_ALLOW_ORIGIN`	The HTTP `Access-Control-Allow-Origin` header field name.
`static String`	`ACCESS_CONTROL_ALLOW_PRIVATE_NETWORK`	The HTTP `Access-Control-Allow-Private-Network` header field name.
`static String`	`ACCESS_CONTROL_EXPOSE_HEADERS`	The HTTP `Access-Control-Expose-Headers` header field name.
`static String`	`ACCESS_CONTROL_MAX_AGE`	The HTTP `Access-Control-Max-Age` header field name.
`static String`	`ACCESS_CONTROL_REQUEST_HEADERS`	The HTTP `Access-Control-Request-Headers` header field name.
`static String`	`ACCESS_CONTROL_REQUEST_METHOD`	The HTTP `Access-Control-Request-Method` header field name.
`static String`	`AGE`	The HTTP `Age` header field name.
`static String`	`ALLOW`	The HTTP `Allow` header field name.
`static String`	`AUTHORIZATION`	The HTTP `Authorization` header field name.
`static String`	`CACHE_CONTROL`	The HTTP `Cache-Control` header field name.
`static String`	`CDN_LOOP`	The HTTP `CDN-Loop` header field name.
`static String`	`CONNECTION`	The HTTP `Connection` header field name.
`static String`	`CONTENT_DISPOSITION`	The HTTP `Content-Disposition` header field name.
`static String`	`CONTENT_ENCODING`	The HTTP `Content-Encoding` header field name.
`static String`	`CONTENT_LANGUAGE`	The HTTP `Content-Language` header field name.
`static String`	`CONTENT_LENGTH`	The HTTP `Content-Length` header field name.
`static String`	`CONTENT_LOCATION`	The HTTP `Content-Location` header field name.
`static String`	`CONTENT_MD5`	The HTTP `Content-MD5` header field name.
`static String`	`CONTENT_RANGE`	The HTTP `Content-Range` header field name.
`static String`	`CONTENT_SECURITY_POLICY`	The HTTP `Content-Security-Policy` header field name.
`static String`	`CONTENT_SECURITY_POLICY_REPORT_ONLY`	The HTTP `Content-Security-Policy-Report-Only` header field name.
`static String`	`CONTENT_TYPE`	The HTTP `Content-Type` header field name.
`static String`	`COOKIE`	The HTTP `Cookie` header field name.
`static String`	`CRITICAL_CH`	The HTTP `Critical-CH` header field name.
`static String`	`CROSS_ORIGIN_EMBEDDER_POLICY`	The HTTP `Cross-Origin-Embedder-Policy` header field name.
`static String`	`CROSS_ORIGIN_EMBEDDER_POLICY_REPORT_ONLY`	The HTTP `Cross-Origin-Embedder-Policy-Report-Only` header field name.
`static String`	`CROSS_ORIGIN_OPENER_POLICY`	The HTTP Cross-Origin-Opener-Policy header field name.
`static String`	`CROSS_ORIGIN_RESOURCE_POLICY`	The HTTP `Cross-Origin-Resource-Policy` header field name.
`static String`	`DATE`	The HTTP `Date` header field name.
`static String`	`DEVICE_MEMORY`	The HTTP `Device-Memory` header field name.
`static String`	`DNT`	The HTTP `DNT` header field name.
`static String`	`DOWNLINK`	The HTTP `Downlink` header field name.
`static String`	`EARLY_DATA`	The HTTP `Early-Data` header field name.
`static String`	`ECT`	The HTTP `ECT` header field name.
`static String`	`ETAG`	The HTTP `ETag` header field name.
`static String`	`EXPECT`	The HTTP `Expect` header field name.
`static String`	`EXPIRES`	The HTTP `Expires` header field name.
`static String`	`FOLLOW_ONLY_WHEN_PRERENDER_SHOWN`	The HTTP `Follow-Only-When-Prerender-Shown` header field name.
`static String`	`FORWARDED`	The HTTP `Forwarded` header field name.
`static String`	`FROM`	The HTTP `From` header field name.
`static String`	`HOST`	The HTTP `Host` header field name.
`static String`	`HTTP2_SETTINGS`	The HTTP `HTTP2-Settings` header field name.
`static String`	`IF_MATCH`	The HTTP `If-Match` header field name.
`static String`	`IF_MODIFIED_SINCE`	The HTTP `If-Modified-Since` header field name.
`static String`	`IF_NONE_MATCH`	The HTTP `If-None-Match` header field name.
`static String`	`IF_RANGE`	The HTTP `If-Range` header field name.
`static String`	`IF_UNMODIFIED_SINCE`	The HTTP `If-Unmodified-Since` header field name.
`static String`	`KEEP_ALIVE`	The HTTP `Keep-Alive` header field name.
`static String`	`LAST_EVENT_ID`	The HTTP `Last-Event-ID` header field name.
`static String`	`LAST_MODIFIED`	The HTTP `Last-Modified` header field name.
`static String`	`LINK`	The HTTP `Link` header field name.
`static String`	`LOCATION`	The HTTP `Location` header field name.
`static String`	`MAX_FORWARDS`	The HTTP `Max-Forwards` header field name.
`static String`	`ORIGIN`	The HTTP `Origin` header field name.
`static String`	`ORIGIN_ISOLATION`	The HTTP `Origin-Isolation` header field name.
`static String`	`ORIGIN_TRIAL`	The HTTP `Origin-Trial` header field name.
`static String`	`P3P`	The HTTP `P3P` header field name.
`static String`	`PERMISSIONS_POLICY`	The HTTP `Permissions-Policy` header field name.
`static String`	`PING_FROM`	The HTTP `Ping-From` header field name.
`static String`	`PING_TO`	The HTTP `Ping-To` header field name.
`static String`	`PRAGMA`	The HTTP `Pragma` header field name.
`static String`	`PROXY_AUTHENTICATE`	The HTTP `Proxy-Authenticate` header field name.
`static String`	`PROXY_AUTHORIZATION`	The HTTP `Proxy-Authorization` header field name.
`static String`	`PUBLIC_KEY_PINS`	The HTTP `Public-Key-Pins` header field name.
`static String`	`PUBLIC_KEY_PINS_REPORT_ONLY`	The HTTP `Public-Key-Pins-Report-Only` header field name.
`static String`	`PURPOSE`	The HTTP `Purpose` header field name.
`static String`	`RANGE`	The HTTP `Range` header field name.
`static String`	`REFERER`	The HTTP `Referer` header field name.
`static String`	`REFERRER_POLICY`	The HTTP `Referrer-Policy` header field name.
`static String`	`REFRESH`	The HTTP `Refresh` header field name.
`static String`	`REPORT_TO`	The HTTP `Report-To` header field name.
`static String`	`RETRY_AFTER`	The HTTP `Retry-After` header field name.
`static String`	`RTT`	The HTTP `RTT` header field name.
`static String`	`SAVE_DATA`	The HTTP `Save-Data` header field name.
`static String`	`SEC_CH_PREFERS_COLOR_SCHEME`	The HTTP `Sec-CH-Prefers-Color-Scheme` header field name.
`static String`	`SEC_CH_UA`	The HTTP `Sec-CH-UA` header field name.
`static String`	`SEC_CH_UA_ARCH`	The HTTP `Sec-CH-UA-Arch` header field name.
`static String`	`SEC_CH_UA_BITNESS`	The HTTP `Sec-CH-UA-Bitness` header field name.
`static String`	`SEC_CH_UA_FULL_VERSION`	Deprecated. Prefer `SEC_CH_UA_FULL_VERSION_LIST`.
`static String`	`SEC_CH_UA_FULL_VERSION_LIST`	The HTTP `Sec-CH-UA-Full-Version` header field name.
`static String`	`SEC_CH_UA_MOBILE`	The HTTP `Sec-CH-UA-Mobile` header field name.
`static String`	`SEC_CH_UA_MODEL`	The HTTP `Sec-CH-UA-Model` header field name.
`static String`	`SEC_CH_UA_PLATFORM`	The HTTP `Sec-CH-UA-Platform` header field name.
`static String`	`SEC_CH_UA_PLATFORM_VERSION`	The HTTP `Sec-CH-UA-Platform-Version` header field name.
`static String`	`SEC_FETCH_DEST`	The HTTP `Sec-Fetch-Dest` header field name.
`static String`	`SEC_FETCH_MODE`	The HTTP `Sec-Fetch-Mode` header field name.
`static String`	`SEC_FETCH_SITE`	The HTTP `Sec-Fetch-Site` header field name.
`static String`	`SEC_FETCH_USER`	The HTTP `Sec-Fetch-User` header field name.
`static String`	`SEC_METADATA`	The HTTP `Sec-Metadata` header field name.
`static String`	`SEC_PROVIDED_TOKEN_BINDING_ID`	The HTTP `Sec-Provided-Token-Binding-ID` header field name.
`static String`	`SEC_REFERRED_TOKEN_BINDING_ID`	The HTTP `Sec-Referred-Token-Binding-ID` header field name.
`static String`	`SEC_TOKEN_BINDING`	The HTTP `Sec-Token-Binding` header field name.
`static String`	`SEC_WEBSOCKET_ACCEPT`	The HTTP `Sec-WebSocket-Accept` header field name.
`static String`	`SEC_WEBSOCKET_EXTENSIONS`	The HTTP `Sec-WebSocket-Extensions` header field name.
`static String`	`SEC_WEBSOCKET_KEY`	The HTTP `Sec-WebSocket-Key` header field name.
`static String`	`SEC_WEBSOCKET_PROTOCOL`	The HTTP `Sec-WebSocket-Protocol` header field name.
`static String`	`SEC_WEBSOCKET_VERSION`	The HTTP `Sec-WebSocket-Version` header field name.
`static String`	`SERVER`	The HTTP `Server` header field name.
`static String`	`SERVER_TIMING`	The HTTP `Server-Timing` header field name.
`static String`	`SERVICE_WORKER`	The HTTP `Service-Worker` header field name.
`static String`	`SERVICE_WORKER_ALLOWED`	The HTTP `Service-Worker-Allowed` header field name.
`static String`	`SET_COOKIE`	The HTTP `Set-Cookie` header field name.
`static String`	`SET_COOKIE2`	The HTTP `Set-Cookie2` header field name.
`static String`	`SOURCE_MAP`	The HTTP `SourceMap` header field name.
`static String`	`STRICT_TRANSPORT_SECURITY`	The HTTP `Strict-Transport-Security` header field name.
`static String`	`TE`	The HTTP `TE` header field name.
`static String`	`TIMING_ALLOW_ORIGIN`	The HTTP `Timing-Allow-Origin` header field name.
`static String`	`TRAILER`	The HTTP `Trailer` header field name.
`static String`	`TRANSFER_ENCODING`	The HTTP `Transfer-Encoding` header field name.
`static String`	`UPGRADE`	The HTTP `Upgrade` header field name.
`static String`	`UPGRADE_INSECURE_REQUESTS`	The HTTP `Upgrade-Insecure-Requests` header field name.
`static String`	`USER_AGENT`	The HTTP `User-Agent` header field name.
`static String`	`VARY`	The HTTP `Vary` header field name.
`static String`	`VIA`	The HTTP `Via` header field name.
`static String`	`VIEWPORT_WIDTH`	The HTTP `Viewport-Width` header field name.
`static String`	`WARNING`	The HTTP `Warning` header field name.
`static String`	`WIDTH`	The HTTP `Width` header field name.
`static String`	`WWW_AUTHENTICATE`	The HTTP `WWW-Authenticate` header field name.
`static String`	`X_CONTENT_SECURITY_POLICY`	The HTTP nonstandard `X-Content-Security-Policy` header field name.
`static String`	`X_CONTENT_SECURITY_POLICY_REPORT_ONLY`	The HTTP nonstandard `X-Content-Security-Policy-Report-Only` header field name.
`static String`	`X_CONTENT_TYPE_OPTIONS`	The HTTP `X-Content-Type-Options` header field name.
`static String`	`X_DEVICE_ACCEPT_LANGUAGE`	The HTTP `X-Device-Accept-Language` header field name.
`static String`	`X_DEVICE_IP`	The HTTP `X-Device-IP` header field name.
`static String`	`X_DEVICE_REFERER`	The HTTP `X-Device-Referer` header field name.
`static String`	`X_DEVICE_REQUESTED_WITH`	The HTTP `X-Device-Requested-With` header field name.
`static String`	`X_DNS_PREFETCH_CONTROL`	The HTTP `X-DNS-Prefetch-Control` header controls DNS prefetch behavior.
`static String`	`X_DO_NOT_TRACK`	The HTTP `X-Do-Not-Track` header field name.
`static String`	`X_DOWNLOAD_OPTIONS`	The HTTP `X-Download-Options` header field name.
`static String`	`X_FORWARDED_FOR`	The HTTP `X-Forwarded-For` header field name (superseded by `Forwarded`).
`static String`	`X_FORWARDED_HOST`	The HTTP `X-Forwarded-Host` header field name.
`static String`	`X_FORWARDED_PORT`	The HTTP `X-Forwarded-Port` header field name.
`static String`	`X_FORWARDED_PROTO`	The HTTP `X-Forwarded-Proto` header field name.
`static String`	`X_FRAME_OPTIONS`	The HTTP `X-Frame-Options` header field name.
`static String`	`X_MOZ`	The HTTP `X-Moz` header field name.
`static String`	`X_POWERED_BY`	The HTTP `X-Powered-By` header field name.
`static String`	`X_PURPOSE`	The HTTP `X-Purpose` header field name.
`static String`	`X_REQUEST_ID`	The HTTP `X-Request-ID` header field name.
`static String`	`X_REQUESTED_WITH`	The HTTP `X-Requested-With` header field name.
`static String`	`X_USER_IP`	The HTTP `X-User-IP` header field name.
`static String`	`X_WEBKIT_CSP`	The HTTP nonstandard `X-WebKit-CSP` header field name.
`static String`	`X_WEBKIT_CSP_REPORT_ONLY`	The HTTP nonstandard `X-WebKit-CSP-Report-Only` header field name.
`static String`	`X_XSS_PROTECTION`	The HTTP `X-XSS-Protection` header field name.

Method Summary
- Methods inherited from class java.lang.Object
  clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - CACHE_CONTROL
```
public static final String CACHE_CONTROL
```
    The HTTP Cache-Control header field name.
    
    See Also:
    
    Constant Field Values
  - CONTENT_LENGTH
```
public static final String CONTENT_LENGTH
```
    The HTTP Content-Length header field name.
    
    See Also:
    
    Constant Field Values
  - CONTENT_TYPE
```
public static final String CONTENT_TYPE
```
    The HTTP Content-Type header field name.
    
    See Also:
    
    Constant Field Values
  - DATE
```
public static final String DATE
```
    The HTTP Date header field name.
    
    See Also:
    
    Constant Field Values
  - PRAGMA
```
public static final String PRAGMA
```
    The HTTP Pragma header field name.
    
    See Also:
    
    Constant Field Values
  - VIA
```
public static final String VIA
```
    The HTTP Via header field name.
    
    See Also:
    
    Constant Field Values
  - WARNING
```
public static final String WARNING
```
    The HTTP Warning header field name.
    
    See Also:
    
    Constant Field Values
  - ACCEPT
```
public static final String ACCEPT
```
    The HTTP Accept header field name.
    
    See Also:
    
    Constant Field Values
  - ACCEPT_CHARSET
```
public static final String ACCEPT_CHARSET
```
    The HTTP Accept-Charset header field name.
    
    See Also:
    
    Constant Field Values
  - ACCEPT_ENCODING
```
public static final String ACCEPT_ENCODING
```
    The HTTP Accept-Encoding header field name.
    
    See Also:
    
    Constant Field Values
  - ACCEPT_LANGUAGE
```
public static final String ACCEPT_LANGUAGE
```
    The HTTP Accept-Language header field name.
    
    See Also:
    
    Constant Field Values
  - ACCESS_CONTROL_REQUEST_HEADERS
```
public static final String ACCESS_CONTROL_REQUEST_HEADERS
```
    The HTTP Access-Control-Request-Headers header field name.
    
    See Also:
    
    Constant Field Values
  - ACCESS_CONTROL_REQUEST_METHOD
```
public static final String ACCESS_CONTROL_REQUEST_METHOD
```
    The HTTP Access-Control-Request-Method header field name.
    
    See Also:
    
    Constant Field Values
  - AUTHORIZATION
```
public static final String AUTHORIZATION
```
    The HTTP Authorization header field name.
    
    See Also:
    
    Constant Field Values
  - CONNECTION
```
public static final String CONNECTION
```
    The HTTP Connection header field name.
    
    See Also:
    
    Constant Field Values
  - COOKIE
```
public static final String COOKIE
```
    The HTTP Cookie header field name.
    
    See Also:
    
    Constant Field Values
  - CROSS_ORIGIN_RESOURCE_POLICY
```
public static final String CROSS_ORIGIN_RESOURCE_POLICY
```
    The HTTP Cross-Origin-Resource-Policy header field name.
    
    Since:
    
    28.0
    
    See Also:
    
    Constant Field Values
  - EARLY_DATA
```
public static final String EARLY_DATA
```
    The HTTP Early-Data header field name.
    
    Since:
    
    27.0
    
    See Also:
    
    Constant Field Values
  - EXPECT
```
public static final String EXPECT
```
    The HTTP Expect header field name.
    
    See Also:
    
    Constant Field Values
  - FROM
```
public static final String FROM
```
    The HTTP From header field name.
    
    See Also:
    
    Constant Field Values
  - FORWARDED
```
public static final String FORWARDED
```
    The HTTP Forwarded header field name.
    
    Since:
    
    20.0
    
    See Also:
    
    Constant Field Values
  - FOLLOW_ONLY_WHEN_PRERENDER_SHOWN
```
public static final String FOLLOW_ONLY_WHEN_PRERENDER_SHOWN
```
    The HTTP Follow-Only-When-Prerender-Shown header field name.
    
    Since:
    
    17.0
    
    See Also:
    
    Constant Field Values
  - HOST
```
public static final String HOST
```
    The HTTP Host header field name.
    
    See Also:
    
    Constant Field Values
  - HTTP2_SETTINGS
```
public static final String HTTP2_SETTINGS
```
    The HTTP HTTP2-Settings header field name.
    
    Since:
    
    24.0
    
    See Also:
    
    Constant Field Values
  - IF_MATCH
```
public static final String IF_MATCH
```
    The HTTP If-Match header field name.
    
    See Also:
    
    Constant Field Values
  - IF_MODIFIED_SINCE
```
public static final String IF_MODIFIED_SINCE
```
    The HTTP If-Modified-Since header field name.
    
    See Also:
    
    Constant Field Values
  - IF_NONE_MATCH
```
public static final String IF_NONE_MATCH
```
    The HTTP If-None-Match header field name.
    
    See Also:
    
    Constant Field Values
  - IF_RANGE
```
public static final String IF_RANGE
```
    The HTTP If-Range header field name.
    
    See Also:
    
    Constant Field Values
  - IF_UNMODIFIED_SINCE
```
public static final String IF_UNMODIFIED_SINCE
```
    The HTTP If-Unmodified-Since header field name.
    
    See Also:
    
    Constant Field Values
  - LAST_EVENT_ID
```
public static final String LAST_EVENT_ID
```
    The HTTP Last-Event-ID header field name.
    
    See Also:
    
    Constant Field Values
  - MAX_FORWARDS
```
public static final String MAX_FORWARDS
```
    The HTTP Max-Forwards header field name.
    
    See Also:
    
    Constant Field Values
  - ORIGIN
```
public static final String ORIGIN
```
    The HTTP Origin header field name.
    
    See Also:
    
    Constant Field Values
  - ORIGIN_ISOLATION
```
public static final String ORIGIN_ISOLATION
```
    The HTTP Origin-Isolation header field name.
    
    Since:
    
    30.1
    
    See Also:
    
    Constant Field Values
  - PROXY_AUTHORIZATION
```
public static final String PROXY_AUTHORIZATION
```
    The HTTP Proxy-Authorization header field name.
    
    See Also:
    
    Constant Field Values
  - RANGE
```
public static final String RANGE
```
    The HTTP Range header field name.
    
    See Also:
    
    Constant Field Values
  - REFERER
```
public static final String REFERER
```
    The HTTP Referer header field name.
    
    See Also:
    
    Constant Field Values
  - REFERRER_POLICY
```
public static final String REFERRER_POLICY
```
    The HTTP Referrer-Policy header field name.
    
    Since:
    
    23.4
    
    See Also:
    
    Constant Field Values
  - SERVICE_WORKER
```
public static final String SERVICE_WORKER
```
    The HTTP Service-Worker header field name.
    
    Since:
    
    20.0
    
    See Also:
    
    Constant Field Values
  - TE
```
public static final String TE
```
    The HTTP TE header field name.
    
    See Also:
    
    Constant Field Values
  - UPGRADE
```
public static final String UPGRADE
```
    The HTTP Upgrade header field name.
    
    See Also:
    
    Constant Field Values
  - UPGRADE_INSECURE_REQUESTS
```
public static final String UPGRADE_INSECURE_REQUESTS
```
    The HTTP Upgrade-Insecure-Requests header field name.
    
    Since:
    
    28.1
    
    See Also:
    
    Constant Field Values
  - USER_AGENT
```
public static final String USER_AGENT
```
    The HTTP User-Agent header field name.
    
    See Also:
    
    Constant Field Values
  - ACCEPT_RANGES
```
public static final String ACCEPT_RANGES
```
    The HTTP Accept-Ranges header field name.
    
    See Also:
    
    Constant Field Values
  - ACCESS_CONTROL_ALLOW_HEADERS
```
public static final String ACCESS_CONTROL_ALLOW_HEADERS
```
    The HTTP Access-Control-Allow-Headers header field name.
    
    See Also:
    
    Constant Field Values
  - ACCESS_CONTROL_ALLOW_METHODS
```
public static final String ACCESS_CONTROL_ALLOW_METHODS
```
    The HTTP Access-Control-Allow-Methods header field name.
    
    See Also:
    
    Constant Field Values
  - ACCESS_CONTROL_ALLOW_ORIGIN
```
public static final String ACCESS_CONTROL_ALLOW_ORIGIN
```
    The HTTP Access-Control-Allow-Origin header field name.
    
    See Also:
    
    Constant Field Values
  - ACCESS_CONTROL_ALLOW_PRIVATE_NETWORK
```
public static final String ACCESS_CONTROL_ALLOW_PRIVATE_NETWORK
```
    The HTTP Access-Control-Allow-Private-Network header field name.
    
    Since:
    
    31.1
    
    See Also:
    
    Constant Field Values
  - ACCESS_CONTROL_ALLOW_CREDENTIALS
```
public static final String ACCESS_CONTROL_ALLOW_CREDENTIALS
```
    The HTTP Access-Control-Allow-Credentials header field name.
    
    See Also:
    
    Constant Field Values
  - ACCESS_CONTROL_EXPOSE_HEADERS
```
public static final String ACCESS_CONTROL_EXPOSE_HEADERS
```
    The HTTP Access-Control-Expose-Headers header field name.
    
    See Also:
    
    Constant Field Values
  - ACCESS_CONTROL_MAX_AGE
```
public static final String ACCESS_CONTROL_MAX_AGE
```
    The HTTP Access-Control-Max-Age header field name.
    
    See Also:
    
    Constant Field Values
  - AGE
```
public static final String AGE
```
    The HTTP Age header field name.
    
    See Also:
    
    Constant Field Values
  - ALLOW
```
public static final String ALLOW
```
    The HTTP Allow header field name.
    
    See Also:
    
    Constant Field Values
  - CONTENT_DISPOSITION
```
public static final String CONTENT_DISPOSITION
```
    The HTTP Content-Disposition header field name.
    
    See Also:
    
    Constant Field Values
  - CONTENT_ENCODING
```
public static final String CONTENT_ENCODING
```
    The HTTP Content-Encoding header field name.
    
    See Also:
    
    Constant Field Values
  - CONTENT_LANGUAGE
```
public static final String CONTENT_LANGUAGE
```
    The HTTP Content-Language header field name.
    
    See Also:
    
    Constant Field Values
  - CONTENT_LOCATION
```
public static final String CONTENT_LOCATION
```
    The HTTP Content-Location header field name.
    
    See Also:
    
    Constant Field Values
  - CONTENT_MD5
```
public static final String CONTENT_MD5
```
    The HTTP Content-MD5 header field name.
    
    See Also:
    
    Constant Field Values
  - CONTENT_RANGE
```
public static final String CONTENT_RANGE
```
    The HTTP Content-Range header field name.
    
    See Also:
    
    Constant Field Values
  - CONTENT_SECURITY_POLICY
```
public static final String CONTENT_SECURITY_POLICY
```
    The HTTP Content-Security-Policy header field name.
    
    Since:
    
    15.0
    
    See Also:
    
    Constant Field Values
  - CONTENT_SECURITY_POLICY_REPORT_ONLY
```
public static final String CONTENT_SECURITY_POLICY_REPORT_ONLY
```
    The HTTP Content-Security-Policy-Report-Only header field name.
    
    Since:
    
    15.0
    
    See Also:
    
    Constant Field Values
  - X_CONTENT_SECURITY_POLICY
```
public static final String X_CONTENT_SECURITY_POLICY
```
    The HTTP nonstandard X-Content-Security-Policy header field name. It was introduced in CSP v.1 and used by the Firefox until version 23 and the Internet Explorer version 10. Please, use CONTENT_SECURITY_POLICY to pass the CSP.
    
    Since:
    
    20.0
    
    See Also:
    
    Constant Field Values
  - X_CONTENT_SECURITY_POLICY_REPORT_ONLY
```
public static final String X_CONTENT_SECURITY_POLICY_REPORT_ONLY
```
    The HTTP nonstandard X-Content-Security-Policy-Report-Only header field name. It was introduced in CSP v.1 and used by the Firefox until version 23 and the Internet Explorer version 10. Please, use CONTENT_SECURITY_POLICY_REPORT_ONLY to pass the CSP.
    
    Since:
    
    20.0
    
    See Also:
    
    Constant Field Values
  - X_WEBKIT_CSP
```
public static final String X_WEBKIT_CSP
```
    The HTTP nonstandard X-WebKit-CSP header field name. It was introduced in CSP v.1 and used by the Chrome until version 25. Please, use CONTENT_SECURITY_POLICY to pass the CSP.
    
    Since:
    
    20.0
    
    See Also:
    
    Constant Field Values
  - X_WEBKIT_CSP_REPORT_ONLY
```
public static final String X_WEBKIT_CSP_REPORT_ONLY
```
    The HTTP nonstandard X-WebKit-CSP-Report-Only header field name. It was introduced in CSP v.1 and used by the Chrome until version 25. Please, use CONTENT_SECURITY_POLICY_REPORT_ONLY to pass the CSP.
    
    Since:
    
    20.0
    
    See Also:
    
    Constant Field Values
  - CROSS_ORIGIN_EMBEDDER_POLICY
```
public static final String CROSS_ORIGIN_EMBEDDER_POLICY
```
    The HTTP Cross-Origin-Embedder-Policy header field name.
    
    Since:
    
    30.0
    
    See Also:
    
    Constant Field Values
  - CROSS_ORIGIN_EMBEDDER_POLICY_REPORT_ONLY
```
public static final String CROSS_ORIGIN_EMBEDDER_POLICY_REPORT_ONLY
```
    The HTTP Cross-Origin-Embedder-Policy-Report-Only header field name.
    
    Since:
    
    30.0
    
    See Also:
    
    Constant Field Values
  - CROSS_ORIGIN_OPENER_POLICY
```
public static final String CROSS_ORIGIN_OPENER_POLICY
```
    The HTTP Cross-Origin-Opener-Policy header field name.
    
    Since:
    
    28.2
    
    See Also:
    
    Constant Field Values
  - ETAG
```
public static final String ETAG
```
    The HTTP ETag header field name.
    
    See Also:
    
    Constant Field Values
  - EXPIRES
```
public static final String EXPIRES
```
    The HTTP Expires header field name.
    
    See Also:
    
    Constant Field Values
  - LAST_MODIFIED
```
public static final String LAST_MODIFIED
```
    The HTTP Last-Modified header field name.
    
    See Also:
    
    Constant Field Values
  - LINK
```
public static final String LINK
```
    The HTTP Link header field name.
    
    See Also:
    
    Constant Field Values
  - LOCATION
```
public static final String LOCATION
```
    The HTTP Location header field name.
    
    See Also:
    
    Constant Field Values
  - KEEP_ALIVE
```
public static final String KEEP_ALIVE
```
    The HTTP Keep-Alive header field name.
    
    Since:
    
    31.0
    
    See Also:
    
    Constant Field Values
  - ORIGIN_TRIAL
```
public static final String ORIGIN_TRIAL
```
    The HTTP Origin-Trial header field name.
    
    Since:
    
    27.1
    
    See Also:
    
    Constant Field Values
  - P3P
```
public static final String P3P
```
    The HTTP P3P header field name. Limited browser support.
    
    See Also:
    
    Constant Field Values
  - PROXY_AUTHENTICATE
```
public static final String PROXY_AUTHENTICATE
```
    The HTTP Proxy-Authenticate header field name.
    
    See Also:
    
    Constant Field Values
  - REFRESH
```
public static final String REFRESH
```
    The HTTP Refresh header field name. Non-standard header supported by most browsers.
    
    See Also:
    
    Constant Field Values
  - REPORT_TO
```
public static final String REPORT_TO
```
    The HTTP Report-To header field name.
    
    Since:
    
    27.1
    
    See Also:
    
    Constant Field Values
  - RETRY_AFTER
```
public static final String RETRY_AFTER
```
    The HTTP Retry-After header field name.
    
    See Also:
    
    Constant Field Values
  - SERVER
```
public static final String SERVER
```
    The HTTP Server header field name.
    
    See Also:
    
    Constant Field Values
  - SERVER_TIMING
```
public static final String SERVER_TIMING
```
    The HTTP Server-Timing header field name.
    
    Since:
    
    23.6
    
    See Also:
    
    Constant Field Values
  - SERVICE_WORKER_ALLOWED
```
public static final String SERVICE_WORKER_ALLOWED
```
    The HTTP Service-Worker-Allowed header field name.
    
    Since:
    
    20.0
    
    See Also:
    
    Constant Field Values
  - SET_COOKIE
```
public static final String SET_COOKIE
```
    The HTTP Set-Cookie header field name.
    
    See Also:
    
    Constant Field Values
  - SET_COOKIE2
```
public static final String SET_COOKIE2
```
    The HTTP Set-Cookie2 header field name.
    
    See Also:
    
    Constant Field Values
  - SOURCE_MAP
```
public static final String SOURCE_MAP
```
    The HTTP SourceMap header field name.
    
    Since:
    
    27.1
    
    See Also:
    
    Constant Field Values
  - STRICT_TRANSPORT_SECURITY
```
public static final String STRICT_TRANSPORT_SECURITY
```
    The HTTP Strict-Transport-Security header field name.
    
    Since:
    
    15.0
    
    See Also:
    
    Constant Field Values
  - TIMING_ALLOW_ORIGIN
```
public static final String TIMING_ALLOW_ORIGIN
```
    The HTTP Timing-Allow-Origin header field name.
    
    Since:
    
    15.0
    
    See Also:
    
    Constant Field Values
  - TRAILER
```
public static final String TRAILER
```
    The HTTP Trailer header field name.
    
    See Also:
    
    Constant Field Values
  - TRANSFER_ENCODING
```
public static final String TRANSFER_ENCODING
```
    The HTTP Transfer-Encoding header field name.
    
    See Also:
    
    Constant Field Values
  - VARY
```
public static final String VARY
```
    The HTTP Vary header field name.
    
    See Also:
    
    Constant Field Values
  - WWW_AUTHENTICATE
```
public static final String WWW_AUTHENTICATE
```
    The HTTP WWW-Authenticate header field name.
    
    See Also:
    
    Constant Field Values
  - DNT
```
public static final String DNT
```
    The HTTP DNT header field name.
    
    See Also:
    
    Constant Field Values
  - X_CONTENT_TYPE_OPTIONS
```
public static final String X_CONTENT_TYPE_OPTIONS
```
    The HTTP X-Content-Type-Options header field name.
    
    See Also:
    
    Constant Field Values
  - X_DEVICE_IP
```
public static final String X_DEVICE_IP
```
    The HTTP X-Device-IP header field name. Header used for VAST requests to provide the IP address of the device on whose behalf the request is being made.
    
    Since:
    
    31.0
    
    See Also:
    
    Constant Field Values
  - X_DEVICE_REFERER
```
public static final String X_DEVICE_REFERER
```
    The HTTP X-Device-Referer header field name. Header used for VAST requests to provide the REFERER header value that the on-behalf-of client would have used when making a request itself.
    
    Since:
    
    31.0
    
    See Also:
    
    Constant Field Values
  - X_DEVICE_ACCEPT_LANGUAGE
```
public static final String X_DEVICE_ACCEPT_LANGUAGE
```
    The HTTP X-Device-Accept-Language header field name. Header used for VAST requests to provide the ACCEPT_LANGUAGE header value that the on-behalf-of client would have used when making a request itself.
    
    Since:
    
    31.0
    
    See Also:
    
    Constant Field Values
  - X_DEVICE_REQUESTED_WITH
```
public static final String X_DEVICE_REQUESTED_WITH
```
    The HTTP X-Device-Requested-With header field name. Header used for VAST requests to provide the X_REQUESTED_WITH header value that the on-behalf-of client would have used when making a request itself.
    
    Since:
    
    31.0
    
    See Also:
    
    Constant Field Values
  - X_DO_NOT_TRACK
```
public static final String X_DO_NOT_TRACK
```
    The HTTP X-Do-Not-Track header field name.
    
    See Also:
    
    Constant Field Values
  - X_FORWARDED_FOR
```
public static final String X_FORWARDED_FOR
```
    The HTTP X-Forwarded-For header field name (superseded by Forwarded).
    
    See Also:
    
    Constant Field Values
  - X_FORWARDED_PROTO
```
public static final String X_FORWARDED_PROTO
```
    The HTTP X-Forwarded-Proto header field name.
    
    See Also:
    
    Constant Field Values
  - X_FORWARDED_HOST
```
public static final String X_FORWARDED_HOST
```
    The HTTP X-Forwarded-Host header field name.
    
    Since:
    
    20.0
    
    See Also:
    
    Constant Field Values
  - X_FORWARDED_PORT
```
public static final String X_FORWARDED_PORT
```
    The HTTP X-Forwarded-Port header field name.
    
    Since:
    
    20.0
    
    See Also:
    
    Constant Field Values
  - X_FRAME_OPTIONS
```
public static final String X_FRAME_OPTIONS
```
    The HTTP X-Frame-Options header field name.
    
    See Also:
    
    Constant Field Values
  - X_POWERED_BY
```
public static final String X_POWERED_BY
```
    The HTTP X-Powered-By header field name.
    
    See Also:
    
    Constant Field Values
  - PUBLIC_KEY_PINS
```
public static final String PUBLIC_KEY_PINS
```
    The HTTP Public-Key-Pins header field name.
    
    Since:
    
    15.0
    
    See Also:
    
    Constant Field Values
  - PUBLIC_KEY_PINS_REPORT_ONLY
```
public static final String PUBLIC_KEY_PINS_REPORT_ONLY
```
    The HTTP Public-Key-Pins-Report-Only header field name.
    
    Since:
    
    15.0
    
    See Also:
    
    Constant Field Values
  - X_REQUEST_ID
```
public static final String X_REQUEST_ID
```
    The HTTP X-Request-ID header field name.
    
    Since:
    
    30.1
    
    See Also:
    
    Constant Field Values
  - X_REQUESTED_WITH
```
public static final String X_REQUESTED_WITH
```
    The HTTP X-Requested-With header field name.
    
    See Also:
    
    Constant Field Values
  - X_USER_IP
```
public static final String X_USER_IP
```
    The HTTP X-User-IP header field name.
    
    See Also:
    
    Constant Field Values
  - X_DOWNLOAD_OPTIONS
```
public static final String X_DOWNLOAD_OPTIONS
```
    The HTTP X-Download-Options header field name.
    When the new X-Download-Options header is present with the value noopen, the user is prevented from opening a file download directly; instead, they must first save the file locally.
    
    Since:
    
    24.1
    
    See Also:
    
    Constant Field Values
  - X_XSS_PROTECTION
```
public static final String X_XSS_PROTECTION
```
    The HTTP X-XSS-Protection header field name.
    
    See Also:
    
    Constant Field Values
  - X_DNS_PREFETCH_CONTROL
```
public static final String X_DNS_PREFETCH_CONTROL
```
    The HTTP X-DNS-Prefetch-Control header controls DNS prefetch behavior. Value can be "on" or "off". By default, DNS prefetching is "on" for HTTP pages and "off" for HTTPS pages.
    
    See Also:
    
    Constant Field Values
  - PING_FROM
```
public static final String PING_FROM
```
    The HTTP Ping-From header field name.
    
    Since:
    
    19.0
    
    See Also:
    
    Constant Field Values
  - PING_TO
```
public static final String PING_TO
```
    The HTTP Ping-To header field name.
    
    Since:
    
    19.0
    
    See Also:
    
    Constant Field Values
  - PURPOSE
```
public static final String PURPOSE
```
    The HTTP Purpose header field name.
    
    Since:
    
    28.0
    
    See Also:
    
    Constant Field Values
  - X_PURPOSE
```
public static final String X_PURPOSE
```
    The HTTP X-Purpose header field name.
    
    Since:
    
    28.0
    
    See Also:
    
    Constant Field Values
  - X_MOZ
```
public static final String X_MOZ
```
    The HTTP X-Moz header field name.
    
    Since:
    
    28.0
    
    See Also:
    
    Constant Field Values
  - DEVICE_MEMORY
```
public static final String DEVICE_MEMORY
```
    The HTTP Device-Memory header field name.
    
    Since:
    
    31.0
    
    See Also:
    
    Constant Field Values
  - DOWNLINK
```
public static final String DOWNLINK
```
    The HTTP Downlink header field name.
    
    Since:
    
    31.0
    
    See Also:
    
    Constant Field Values
  - ECT
```
public static final String ECT
```
    The HTTP ECT header field name.
    
    Since:
    
    31.0
    
    See Also:
    
    Constant Field Values
  - RTT
```
public static final String RTT
```
    The HTTP RTT header field name.
    
    Since:
    
    31.0
    
    See Also:
    
    Constant Field Values
  - SAVE_DATA
```
public static final String SAVE_DATA
```
    The HTTP Save-Data header field name.
    
    Since:
    
    31.0
    
    See Also:
    
    Constant Field Values
  - VIEWPORT_WIDTH
```
public static final String VIEWPORT_WIDTH
```
    The HTTP Viewport-Width header field name.
    
    Since:
    
    31.0
    
    See Also:
    
    Constant Field Values
  - WIDTH
```
public static final String WIDTH
```
    The HTTP Width header field name.
    
    Since:
    
    31.0
    
    See Also:
    
    Constant Field Values
  - PERMISSIONS_POLICY
```
public static final String PERMISSIONS_POLICY
```
    The HTTP Permissions-Policy header field name.
    
    Since:
    
    31.0
    
    See Also:
    
    Constant Field Values
  - SEC_CH_PREFERS_COLOR_SCHEME
```
public static final String SEC_CH_PREFERS_COLOR_SCHEME
```
    The HTTP Sec-CH-Prefers-Color-Scheme header field name.
    This header is experimental.
    
    Since:
    
    31.0
    
    See Also:
    
    Constant Field Values
  - ACCEPT_CH
```
public static final String ACCEPT_CH
```
    The HTTP Accept-CH header field name.
    
    Since:
    
    31.0
    
    See Also:
    
    Constant Field Values
  - CRITICAL_CH
```
public static final String CRITICAL_CH
```
    The HTTP Critical-CH header field name.
    
    Since:
    
    31.0
    
    See Also:
    
    Constant Field Values
  - SEC_CH_UA
```
public static final String SEC_CH_UA
```
    The HTTP Sec-CH-UA header field name.
    
    Since:
    
    30.0
    
    See Also:
    
    Constant Field Values
  - SEC_CH_UA_ARCH
```
public static final String SEC_CH_UA_ARCH
```
    The HTTP Sec-CH-UA-Arch header field name.
    
    Since:
    
    30.0
    
    See Also:
    
    Constant Field Values
  - SEC_CH_UA_MODEL
```
public static final String SEC_CH_UA_MODEL
```
    The HTTP Sec-CH-UA-Model header field name.
    
    Since:
    
    30.0
    
    See Also:
    
    Constant Field Values
  - SEC_CH_UA_PLATFORM
```
public static final String SEC_CH_UA_PLATFORM
```
    The HTTP Sec-CH-UA-Platform header field name.
    
    Since:
    
    30.0
    
    See Also:
    
    Constant Field Values
  - SEC_CH_UA_PLATFORM_VERSION
```
public static final String SEC_CH_UA_PLATFORM_VERSION
```
    The HTTP Sec-CH-UA-Platform-Version header field name.
    
    Since:
    
    30.0
    
    See Also:
    
    Constant Field Values
  - SEC_CH_UA_FULL_VERSION
```
@Deprecated
public static final String SEC_CH_UA_FULL_VERSION
```
    Deprecated.
    Prefer SEC_CH_UA_FULL_VERSION_LIST.
    
    The HTTP Sec-CH-UA-Full-Version header field name.
    
    Since:
    
    30.0
    
    See Also:
    
    Constant Field Values
  - SEC_CH_UA_FULL_VERSION_LIST
```
public static final String SEC_CH_UA_FULL_VERSION_LIST
```
    The HTTP Sec-CH-UA-Full-Version header field name.
    
    Since:
    
    31.1
    
    See Also:
    
    Constant Field Values
  - SEC_CH_UA_MOBILE
```
public static final String SEC_CH_UA_MOBILE
```
    The HTTP Sec-CH-UA-Mobile header field name.
    
    Since:
    
    30.0
    
    See Also:
    
    Constant Field Values
  - SEC_CH_UA_BITNESS
```
public static final String SEC_CH_UA_BITNESS
```
    The HTTP Sec-CH-UA-Bitness header field name.
    
    Since:
    
    31.0
    
    See Also:
    
    Constant Field Values
  - SEC_FETCH_DEST
```
public static final String SEC_FETCH_DEST
```
    The HTTP Sec-Fetch-Dest header field name.
    
    Since:
    
    27.1
    
    See Also:
    
    Constant Field Values
  - SEC_FETCH_MODE
```
public static final String SEC_FETCH_MODE
```
    The HTTP Sec-Fetch-Mode header field name.
    
    Since:
    
    27.1
    
    See Also:
    
    Constant Field Values
  - SEC_FETCH_SITE
```
public static final String SEC_FETCH_SITE
```
    The HTTP Sec-Fetch-Site header field name.
    
    Since:
    
    27.1
    
    See Also:
    
    Constant Field Values
  - SEC_FETCH_USER
```
public static final String SEC_FETCH_USER
```
    The HTTP Sec-Fetch-User header field name.
    
    Since:
    
    27.1
    
    See Also:
    
    Constant Field Values
  - SEC_METADATA
```
public static final String SEC_METADATA
```
    The HTTP Sec-Metadata header field name.
    
    Since:
    
    26.0
    
    See Also:
    
    Constant Field Values
  - SEC_TOKEN_BINDING
```
public static final String SEC_TOKEN_BINDING
```
    The HTTP Sec-Token-Binding header field name.
    
    Since:
    
    25.1
    
    See Also:
    
    Constant Field Values
  - SEC_PROVIDED_TOKEN_BINDING_ID
```
public static final String SEC_PROVIDED_TOKEN_BINDING_ID
```
    The HTTP Sec-Provided-Token-Binding-ID header field name.
    
    Since:
    
    25.1
    
    See Also:
    
    Constant Field Values
  - SEC_REFERRED_TOKEN_BINDING_ID
```
public static final String SEC_REFERRED_TOKEN_BINDING_ID
```
    The HTTP Sec-Referred-Token-Binding-ID header field name.
    
    Since:
    
    25.1
    
    See Also:
    
    Constant Field Values
  - SEC_WEBSOCKET_ACCEPT
```
public static final String SEC_WEBSOCKET_ACCEPT
```
    The HTTP Sec-WebSocket-Accept header field name.
    
    Since:
    
    28.0
    
    See Also:
    
    Constant Field Values
  - SEC_WEBSOCKET_EXTENSIONS
```
public static final String SEC_WEBSOCKET_EXTENSIONS
```
    The HTTP Sec-WebSocket-Extensions header field name.
    
    Since:
    
    28.0
    
    See Also:
    
    Constant Field Values
  - SEC_WEBSOCKET_KEY
```
public static final String SEC_WEBSOCKET_KEY
```
    The HTTP Sec-WebSocket-Key header field name.
    
    Since:
    
    28.0
    
    See Also:
    
    Constant Field Values
  - SEC_WEBSOCKET_PROTOCOL
```
public static final String SEC_WEBSOCKET_PROTOCOL
```
    The HTTP Sec-WebSocket-Protocol header field name.
    
    Since:
    
    28.0
    
    See Also:
    
    Constant Field Values
  - SEC_WEBSOCKET_VERSION
```
public static final String SEC_WEBSOCKET_VERSION
```
    The HTTP Sec-WebSocket-Version header field name.
    
    Since:
    
    28.0
    
    See Also:
    
    Constant Field Values
  - CDN_LOOP
```
public static final String CDN_LOOP
```
    The HTTP CDN-Loop header field name.
    
    Since:
    
    28.0
    
    See Also:
    
    Constant Field Values

Class HttpHeaders

Nested Class Summary

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

CACHE_CONTROL

CONTENT_LENGTH

CONTENT_TYPE

DATE

PRAGMA

VIA

WARNING

ACCEPT

ACCEPT_CHARSET

ACCEPT_ENCODING

ACCEPT_LANGUAGE

ACCESS_CONTROL_REQUEST_HEADERS

ACCESS_CONTROL_REQUEST_METHOD

AUTHORIZATION

CONNECTION

COOKIE

CROSS_ORIGIN_RESOURCE_POLICY

EARLY_DATA

EXPECT

FROM

FORWARDED

FOLLOW_ONLY_WHEN_PRERENDER_SHOWN

HOST

HTTP2_SETTINGS

IF_MATCH

IF_MODIFIED_SINCE

IF_NONE_MATCH

IF_RANGE

IF_UNMODIFIED_SINCE

LAST_EVENT_ID

MAX_FORWARDS

ORIGIN

ORIGIN_ISOLATION

PROXY_AUTHORIZATION

RANGE

REFERER

REFERRER_POLICY

SERVICE_WORKER

TE

UPGRADE

UPGRADE_INSECURE_REQUESTS

USER_AGENT

ACCEPT_RANGES

ACCESS_CONTROL_ALLOW_HEADERS

ACCESS_CONTROL_ALLOW_METHODS

ACCESS_CONTROL_ALLOW_ORIGIN

ACCESS_CONTROL_ALLOW_PRIVATE_NETWORK

ACCESS_CONTROL_ALLOW_CREDENTIALS

ACCESS_CONTROL_EXPOSE_HEADERS

ACCESS_CONTROL_MAX_AGE

AGE

ALLOW

CONTENT_DISPOSITION

CONTENT_ENCODING

CONTENT_LANGUAGE

CONTENT_LOCATION

CONTENT_MD5

CONTENT_RANGE

CONTENT_SECURITY_POLICY

CONTENT_SECURITY_POLICY_REPORT_ONLY

X_CONTENT_SECURITY_POLICY

X_CONTENT_SECURITY_POLICY_REPORT_ONLY

X_WEBKIT_CSP

X_WEBKIT_CSP_REPORT_ONLY

CROSS_ORIGIN_EMBEDDER_POLICY

CROSS_ORIGIN_EMBEDDER_POLICY_REPORT_ONLY

CROSS_ORIGIN_OPENER_POLICY

ETAG

EXPIRES

LAST_MODIFIED

LINK

LOCATION

KEEP_ALIVE

ORIGIN_TRIAL