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BaseDexClassLoader
public class BaseDexClassLoader
extends ClassLoader
Known direct subclasses DexClassLoader | A class loader that loads classes from .jar and .apk files containing a classes.dex entry. | InMemoryDexClassLoader | A ClassLoader implementation that loads classes from a buffer containing a DEX file. | PathClassLoader | Provides a simple ClassLoader implementation that operates on a list of files and directories in the local file system, but does not attempt to load classes from the network. | |
Known indirect subclasses |
Base class for common functionality between various dex-based ClassLoader
implementations.
Summary
Inherited methods |
From class java.lang.ClassLoader void | clearAssertionStatus() Sets the default assertion status for this class loader to false and discards any package defaults or class assertion status settings associated with the class loader. | final Class<?> | defineClass(String name, byte[] b, int off, int len, ProtectionDomain protectionDomain) Converts an array of bytes into an instance of class Class , with a given ProtectionDomain . | final Class<?> | defineClass(String name, ByteBuffer b, ProtectionDomain protectionDomain) Converts a ByteBuffer into an instance of class Class , with the given ProtectionDomain . | final Class<?> | defineClass(byte[] b, int off, int len) This method was deprecated in API level 15. Replaced by defineClass(String, byte[], int, int) | final Class<?> | defineClass(String name, byte[] b, int off, int len) Converts an array of bytes into an instance of class Class . | Package | definePackage(String name, String specTitle, String specVersion, String specVendor, String implTitle, String implVersion, String implVendor, URL sealBase) Defines a package by name in this ClassLoader . | Class<?> | findClass(String name) Finds the class with the specified binary name. | String | findLibrary(String libname) Returns the absolute path name of a native library. | final Class<?> | findLoadedClass(String name) Returns the class with the given binary name if this loader has been recorded by the Java virtual machine as an initiating loader of a class with that binary name. | URL | findResource(String name) Finds the resource with the given name. | Enumeration<URL> | findResources(String name) Returns an enumeration of URL objects representing all the resources with the given name. | final Class<?> | findSystemClass(String name) Finds a class with the specified binary name, loading it if necessary. | Package | getPackage(String name) This method was deprecated in API level 35. If multiple class loaders delegate to each other and define classes with the same package name, and one such loader relies on the lookup behavior of getPackage to return a Package from a parent loader, then the properties exposed by the Package may not be as expected in the rest of the program. For example, the Package will only expose annotations from the package-info.class file defined by the parent loader, even if annotations exist in a package-info.class file defined by a child loader. | Package[] | getPackages() Returns all of the Package s that have been defined by this class loader and its ancestors. | final ClassLoader | getParent() Returns the parent class loader for delegation. | URL | getResource(String name) Finds the resource with the given name. | InputStream | getResourceAsStream(String name) Returns an input stream for reading the specified resource. | Enumeration<URL> | getResources(String name) Finds all the resources with the given name. | static ClassLoader | getSystemClassLoader() Returns the system class loader. | static URL | getSystemResource(String name) Find a resource of the specified name from the search path used to load classes. | static InputStream | getSystemResourceAsStream(String name) Open for reading, a resource of the specified name from the search path used to load classes. | static Enumeration<URL> | getSystemResources(String name) Finds all resources of the specified name from the search path used to load classes. | Class<?> | loadClass(String name, boolean resolve) Loads the class with the specified binary name. | Class<?> | loadClass(String name) Loads the class with the specified binary name. | static boolean | registerAsParallelCapable() Registers the caller as #isRegisteredAsParallelCapable() parallel capable . | final void | resolveClass(Class<?> c) Links the specified class. | void | setClassAssertionStatus(String className, boolean enabled) Sets the desired assertion status for the named top-level class in this class loader and any nested classes contained therein. | void | setDefaultAssertionStatus(boolean enabled) Sets the default assertion status for this class loader. | void | setPackageAssertionStatus(String packageName, boolean enabled) Sets the package default assertion status for the named package. | final void | setSigners(Class<?> c, Object[] signers) Sets the signers of a class. | |
From class java.lang.Object Object | clone() Creates and returns a copy of this object. | boolean | equals(Object obj) Indicates whether some other object is "equal to" this one. | void | finalize() Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. | final Class<?> | getClass() Returns the runtime class of this Object . | int | hashCode() Returns a hash code value for the object. | final void | notify() Wakes up a single thread that is waiting on this object's monitor. | final void | notifyAll() Wakes up all threads that are waiting on this object's monitor. | String | toString() Returns a string representation of the object. | final void | wait(long timeoutMillis, int nanos) Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed. | final void | wait(long timeoutMillis) Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed. | final void | wait() Causes the current thread to wait until it is awakened, typically by being notified or interrupted. | |
Public constructors
BaseDexClassLoader
public BaseDexClassLoader (String dexPath, File optimizedDirectory, String librarySearchPath, ClassLoader parent)
Constructs an instance. Note that all the *.jar and *.apk files from dexPath
might be first extracted in-memory before the code is loaded. This can be avoided by passing raw dex files (*.dex) in the dexPath
.
Parameters |
dexPath | String : the list of jar/apk files containing classes and resources, delimited by File.pathSeparator , which defaults to ":" on Android. |
optimizedDirectory | File : this parameter is deprecated and has no effect since API level 26. |
librarySearchPath | String : the list of directories containing native libraries, delimited by File.pathSeparator ; may be null |
parent | ClassLoader : the parent class loader |
Public methods
findLibrary
public String findLibrary (String name)
Returns the absolute path name of a native library. The VM invokes this method to locate the native libraries that belong to classes loaded with this class loader. If this method returns null
, the VM searches the library along the path specified as the "java.library.path
" property.
Parameters |
name | String : The library name |
Returns |
String | The absolute path of the native library |
toString
public String toString ()
Returns a string representation of the object.
Returns |
String | a string representation of the object. |
Protected methods
findClass
protected Class<?> findClass (String name)
Finds the class with the specified binary name. This method should be overridden by class loader implementations that follow the delegation model for loading classes, and will be invoked by the loadClass
method after checking the parent class loader for the requested class.
Returns |
Class<?> | The resulting Class object |
findResource
protected URL findResource (String name)
Finds the resource with the given name. Class loader implementations should override this method.
Parameters |
name | String : The resource name |
Returns |
URL | URL object for reading the resource; null if the resource could not be found, a URL could not be constructed to locate the resource, the resource is in a package that is not opened unconditionally, or access to the resource is denied by the security manager. |
findResources
protected Enumeration<URL> findResources (String name)
Returns an enumeration of URL
objects representing all the resources with the given name. Class loader implementations should override this method.
Parameters |
name | String : The resource name |
Returns |
Enumeration<URL> | An enumeration of URL objects for the resource. If no resources could be found, the enumeration will be empty. Resources for which a URL cannot be constructed, are in a package that is not opened unconditionally, or access to the resource is denied by the security manager, are not returned in the enumeration. |
getPackage
protected Package getPackage (String name)
This method is deprecated.
See ClassLoader.getPackage(String)
Returns package information for the given package. Unfortunately, instances of this class don'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 fake 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 is 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 which were loaded by different ClassLoader
instances. This is rather unlikely, and given that this whole thing is more or less a workaround, probably not worth the effort to address.
Parameters |
name | String : the name of the class |
Returns |
Package | the package information for the class, or null if there is no package information available for it |
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Last updated 2025-02-10 UTC.
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