ModuleReference (Java SE 12 & JDK 12 )

java.lang.Object
- java.lang.module.ModuleReference

```
public abstract class ModuleReference
extends Object
```
A reference to a module's content.
A module reference is a concrete implementation of this class that implements the abstract methods defined by this class. It contains the module's descriptor and its location, if known. It also has the ability to create a ModuleReader in order to access the module's content, which may be inside the Java run-time system itself or in an artifact such as a modular JAR file.

Since:

9

See Also:

ModuleFinder, ModuleReader

Constructor Summary

Constructors
Modifier Constructor Description

protected ModuleReference(ModuleDescriptor descriptor, URI location)
Constructs a new instance of this class.

Method Summary

Modifier and Type	Method	Description
`ModuleDescriptor`	`descriptor()`	Returns the module descriptor.
`Optional<URI>`	`location()`	Returns the location of this module's content, if known.
`abstract ModuleReader`	`open()`	Opens the module content for reading.

Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - ModuleReference
```
protected ModuleReference(ModuleDescriptor descriptor,
                          URI location)
```
    Constructs a new instance of this class.
    
    Parameters:
    
    descriptor - The module descriptor
    
    location - The module location or null if not known
- Method Detail
  - descriptor
```
public final ModuleDescriptor descriptor()
```
    Returns the module descriptor.
    
    Returns:
    
    The module descriptor
  - location
```
public final Optional<URI> location()
```
    Returns the location of this module's content, if known.
    This URI, when present, can be used as the location value of a CodeSource so that a module's classes can be granted specific permissions when loaded by a SecureClassLoader.
    
    Returns:
    
    The location or an empty Optional if not known
  - open
```
public abstract ModuleReader open()
                           throws IOException
```
    Opens the module content for reading.
    
    Returns:
    
    A ModuleReader to read the module
    
    Throws:
    
    IOException - If an I/O error occurs
    
    SecurityException - If denied by the security manager