Summary: Ctors | Protected Methods | Inherited Methods | [Expand All]

Since: API Level 3

public class

DexClassLoader

extends ClassLoader

java.lang.Object
↳	java.lang.ClassLoader
	↳	dalvik.system.DexClassLoader

Class Overview

Provides a simple ClassLoader implementation that operates on a list of jar/apk files with classes.dex entries. The directory that holds the optimized form of the files is specified explicitly. This can be used to execute code not installed as part of an application. The best place to put the optimized DEX files is in app-specific storage, so that removal of the app will automatically remove the optimized DEX files. If other storage is used (e.g. /sdcard), the app may not have an opportunity to remove them.

Summary

Public Constructors
	DexClassLoader(String dexPath, String dexOutputDir, String libPath, ClassLoader parent) Creates a `DexClassLoader` that finds interpreted and native code.

Protected Methods
Class<?>	findClass(String name) Finds a class.
String	findLibrary(String libname) Finds a native library.
URL	findResource(String name) Finds a resource.
Package	getPackage(String name) Returns package information for the given package.

[Expand]

Inherited Methods

From class java.lang.ClassLoader

void	clearAssertionStatus() Sets the default assertion status for this class loader to `false` and removes any package default and class assertion status settings.
final Class<?>	defineClass(String name, ByteBuffer b, ProtectionDomain protectionDomain) Defines a new class with the specified name, byte code from the byte buffer and the optional protection domain.
final Class<?>	defineClass(String className, byte[] classRep, int offset, int length, ProtectionDomain protectionDomain) Constructs a new class from an array of bytes containing a class definition in class file format and assigns the specified protection domain to the new class.
final Class<?>	defineClass(String className, byte[] classRep, int offset, int length) Constructs a new class from an array of bytes containing a class definition in class file format.
final Class<?>	defineClass(byte[] classRep, int offset, int length) This method is deprecated. Use `defineClass(String, byte[], int, int)`
Package	definePackage(String name, String specTitle, String specVersion, String specVendor, String implTitle, String implVersion, String implVendor, URL sealBase) Defines and returns a new `Package` using the specified information.
Class<?>	findClass(String className) Overridden by subclasses, throws a `ClassNotFoundException` by default.
String	findLibrary(String libName) Returns the absolute path of the native library with the specified name, or `null`.
final Class<?>	findLoadedClass(String className) Returns the class with the specified name if it has already been loaded by the virtual machine or `null` if it has not yet been loaded.
URL	findResource(String resName) Finds the URL of the resource with the specified name.
Enumeration<URL>	findResources(String resName) Finds an enumeration of URLs for the resource with the specified name.
final Class<?>	findSystemClass(String className) Finds the class with the specified name, loading it using the system class loader if necessary.
Package	getPackage(String name) Returns the package with the specified name.
Package[]	getPackages() Returns all the packages known to this class loader.
final ClassLoader	getParent() Returns this class loader's parent.
URL	getResource(String resName) Returns the URL of the resource with the specified name.
InputStream	getResourceAsStream(String resName) Returns a stream for the resource with the specified name.
Enumeration<URL>	getResources(String resName) Returns an enumeration of URLs for the resource with the specified name.
static ClassLoader	getSystemClassLoader() Returns the system class loader.
static URL	getSystemResource(String resName) Finds the URL of the resource with the specified name.
static InputStream	getSystemResourceAsStream(String resName) Returns a stream for the resource with the specified name.
static Enumeration<URL>	getSystemResources(String resName) Returns an enumeration of URLs for the resource with the specified name.
Class<?>	loadClass(String className, boolean resolve) Loads the class with the specified name, optionally linking it after loading.
Class<?>	loadClass(String className) Loads the class with the specified name.
final void	resolveClass(Class<?> clazz) Forces a class to be linked (initialized).
void	setClassAssertionStatus(String cname, boolean enable) Sets the assertion status of the class with the specified name.
void	setDefaultAssertionStatus(boolean enable) Sets the default assertion status for this class loader.
void	setPackageAssertionStatus(String pname, boolean enable) Sets the assertion status of the package with the specified name.
final void	setSigners(Class<?> c, Object[] signers) Sets the signers of the specified class.

From class java.lang.Object

Object	clone() Creates and returns a copy of this `Object`.
boolean	equals(Object o) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Called before the object's memory is reclaimed by the VM.
final Class<?>	getClass() Returns the unique instance of `Class` that represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait() Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object.
final void	wait(long millis, int nanos) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.
final void	wait(long millis) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.

Public Constructors

public DexClassLoader (String dexPath, String dexOutputDir, String libPath, ClassLoader parent)

Since: API Level 3

Creates a DexClassLoader that finds interpreted and native code. Interpreted classes are found in a set of DEX files contained in Jar or APK files. The path lists are separated using the character specified by the "path.separator" system property, which defaults to ":".

Parameters

dexPath	the list of jar/apk files containing classes and resources
dexOutputDir	directory where optimized DEX files should be written
libPath	the list of directories containing native libraries; may be null
parent	the parent class loader

Protected Methods

protected Class<?> findClass (String name)

Since: API Level 3

Finds a class. This method is called by loadClass() after the parent ClassLoader has failed to find a loaded class of the same name.

Parameters

name	The name of the class to search for, in a human-readable form like "java.lang.String" or "java.net.URLClassLoader$3$1".

Returns

the Class object representing the class

Throws

ClassNotFoundException	if the class cannot be found

protected String findLibrary (String libname)

Since: API Level 3

Finds a native library. This method is called after the parent ClassLoader has failed to find a native library of the same name.

Parameters

libname	The name of the library to find

Returns

the complete path of the library, or null if the library is not found.

protected URL findResource (String name)

Since: API Level 3

Finds a resource. This method is called by getResource() after the parent ClassLoader has failed to find a loaded resource of the same name.

Parameters

name	The name of the resource to find

Returns

the location of the resource as a URL, or null if the resource is not found.

protected Package getPackage (String name)

Since: API Level 3

Returns package information for the given package. Unfortunately, the DexClassLoader doesn't really have this information, and as a non-secure ClassLoader, it isn't even required to, according to the spec. Yet, we want to provide it, in order to make all those hopeful callers of myClass.getPackage().getName() happy. Thus we construct a Package object the first time it is being requested and fill most of the fields with dummy values. The Package object is then put into the ClassLoader's Package cache, so we see the same one next time. We don't create Package objects for null arguments or for the default package.

There a limited chance that we end up with multiple Package objects representing the same package: It can happen when when a package is scattered across different JAR files being loaded by different ClassLoaders. Rather unlikely, and given that this whole thing is more or less a workaround, probably not worth the effort.

Parameters

name	the name of the class

Returns

the package information for the class, or null if there is not package information available for it

Classes

DexClassLoader

Class Overview

Summary

Public Constructors

public DexClassLoader (String dexPath, String dexOutputDir, String libPath, ClassLoader parent)

Parameters

Protected Methods

protected Class<?> findClass (String name)

Parameters

Returns

Throws

protected String findLibrary (String libname)

Parameters

Returns

protected URL findResource (String name)

Parameters

Returns

protected Package getPackage (String name)

Parameters

Returns