Added in API level 3

DexClassLoader

open class DexClassLoader : BaseDexClassLoader

kotlin.Any
↳	java.lang.ClassLoader
	↳	dalvik.system.BaseDexClassLoader
		↳	dalvik.system.DexClassLoader

A class loader that loads classes from .jar and .apk files containing a classes.dex entry. This can be used to execute code not installed as part of an application.

Prior to API level 26, this class loader requires an application-private, writable directory to cache optimized classes. Use Context.getCodeCacheDir() to create such a directory:

<code>File dexOutputDir = context.getCodeCacheDir();
  </code>

Do not cache optimized classes on external storage. External storage does not provide access controls necessary to protect your application from code injection attacks.

Summary

Public constructors
DexClassLoader(dexPath: String!, optimizedDirectory: String!, librarySearchPath: String!, parent: ClassLoader!) Creates a DexClassLoader that finds interpreted and native code.

Inherited functions
From class ClassLoader Unit 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. This method is provided so that class loaders can be made to ignore any command line or persistent assertion status settings and "start with a clean slate." Android-note: AssertionStatuses are unsupported. This method is a no-op. Class<*>! defineClass(b: ByteArray!, off: Int, len: Int) Converts an array of bytes into an instance of class Class. Before the Class can be used it must be resolved. This method is deprecated in favor of the version that takes a binary name as its first argument, and is more secure. Class<*>! defineClass(name: String!, b: ByteArray!, off: Int, len: Int) Converts an array of bytes into an instance of class Class. Before the Class can be used it must be resolved. This method assigns a default ProtectionDomain to the newly defined class. The ProtectionDomain is effectively granted the same set of permissions returned when Policy.getPolicy().getPermissions(new CodeSource(null, null)) is invoked. The default protection domain is created on the first invocation of defineClass, and re-used on subsequent invocations. To assign a specific ProtectionDomain to the class, use the defineClass method that takes a ProtectionDomain as one of its arguments. This method defines a package in this class loader corresponding to the package of the Class (if such a package has not already been defined in this class loader). The name of the defined package is derived from the binary name of the class specified by the byte array b. Other properties of the defined package are as specified by Package. Class<*>! defineClass(name: String!, b: ByteArray!, off: Int, len: Int, protectionDomain: ProtectionDomain!) Converts an array of bytes into an instance of class Class, with a given ProtectionDomain. If the given ProtectionDomain is null, then a default protection domain will be assigned to the class as specified in the documentation for defineClass(java.lang.String,byte[],int,int). Before the class can be used it must be resolved. The first class defined in a package determines the exact set of certificates that all subsequent classes defined in that package must contain. The set of certificates for a class is obtained from the CodeSource within the ProtectionDomain of the class. Any classes added to that package must contain the same set of certificates or a SecurityException will be thrown. Note that if name is null, this check is not performed. You should always pass in the binary name of the class you are defining as well as the bytes. This ensures that the class you are defining is indeed the class you think it is. This method defines a package in this class loader corresponding to the package of the Class (if such a package has not already been defined in this class loader). The name of the defined package is derived from the binary name of the class specified by the byte array b. Other properties of the defined package are as specified by Package. Class<*>! defineClass(name: String!, b: ByteBuffer!, protectionDomain: ProtectionDomain!) Converts a ByteBuffer into an instance of class Class, with the given ProtectionDomain. If the given ProtectionDomain is null, then a default protection domain will be assigned to the class as specified in the documentation for defineClass(java.lang.String,byte[],int,int). Before the class can be used it must be resolved. The rules about the first class defined in a package determining the set of certificates for the package, the restrictions on class names, and the defined package of the class are identical to those specified in the documentation for defineClass(java.lang.String,byte[],int,int,java.security.ProtectionDomain). An invocation of this method of the form cl.defineClass(name, bBuffer, pd) yields exactly the same result as the statements ... byte[] temp = new byte[bBuffer.remaining()]; bBuffer. get(temp); return cl.defineClass(name, temp, 0, temp.length, pd); Package! definePackage(name: String!, specTitle: String!, specVersion: String!, specVendor: String!, implTitle: String!, implVersion: String!, implVendor: String!, sealBase: URL!) Defines a package by name in this ClassLoader. Package names must be unique within a class loader and cannot be redefined or changed once created. If a class loader wishes to define a package with specific properties, such as version information, then the class loader should call this definePackage method before calling defineClass. Otherwise, the defineClass method will define a package in this class loader corresponding to the package of the newly defined class; the properties of this defined package are specified by Package. Class<*>! findLoadedClass(name: String!) 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. Otherwise null is returned. Class<*>! findSystemClass(name: String!) Finds a class with the specified binary name, loading it if necessary. This method loads the class through the system class loader (see getSystemClassLoader()). The Class object returned might have more than one ClassLoader associated with it. Subclasses of ClassLoader need not usually invoke this method, because most class loaders need to override just findClass(java.lang.String). Array<Package!>! getPackages() Returns all of the Packages that have been defined by this class loader and its ancestors. The returned array may contain more than one Package object of the same package name, each defined by a different class loader in the class loader hierarchy. ClassLoader! getParent() Returns the parent class loader for delegation. Some implementations may use null to represent the bootstrap class loader. This method will return null in such implementations if this class loader's parent is the bootstrap class loader. URL! getResource(name: String!) Finds the resource with the given name. A resource is some data (images, audio, text, etc) that can be accessed by class code in a way that is independent of the location of the code. The name of a resource is a '/'-separated path name thatf identifies the resource. InputStream! getResourceAsStream(name: String!) Returns an input stream for reading the specified resource. The search order is described in the documentation for getResource(java.lang.String). Enumeration<URL!>! getResources(name: String!) Finds all the resources with the given name. A resource is some data (images, audio, text, etc) that can be accessed by class code in a way that is independent of the location of the code. The name of a resource is a /-separated path name that identifies the resource. ClassLoader! getSystemClassLoader() Returns the system class loader. This is the default delegation parent for new ClassLoader instances, and is typically the class loader used to start the application. This method is first invoked early in the runtime's startup sequence, at which point it creates the system class loader. This class loader will be the context class loader for the main application thread (for example, the thread that invokes the main method of the main class). The default system class loader is an implementation-dependent instance of this class. URL! getSystemResource(name: String!) Find a resource of the specified name from the search path used to load classes. This method locates the resource through the system class loader (see getSystemClassLoader()). InputStream! getSystemResourceAsStream(name: String!) Open for reading, a resource of the specified name from the search path used to load classes. This method locates the resource through the system class loader (see getSystemClassLoader()). Enumeration<URL!>! getSystemResources(name: String!) Finds all resources of the specified name from the search path used to load classes. The resources thus found are returned as an Enumeration of objects. The search order is described in the documentation for getSystemResource(java.lang.String). Class<*>! loadClass(name: String!) Loads the class with the specified binary name. This method searches for classes in the same manner as the loadClass(java.lang.String,boolean) method. It is invoked by the Java virtual machine to resolve class references. Invoking this method is equivalent to invoking loadClass(name,. Class<*>! loadClass(name: String!, resolve: Boolean) Loads the class with the specified binary name. The default implementation of this method searches for classes in the following order: Invoke findLoadedClass(java.lang.String) to check if the class has already been loaded. Invoke the loadClass method on the parent class loader. If the parent is null the class loader built into the virtual machine is used, instead. Invoke the findClass(java.lang.String) method to find the class. If the class was found using the above steps, and the resolve flag is true, this method will then invoke the resolveClass(java.lang.Class) method on the resulting Class object. Subclasses of ClassLoader are encouraged to override findClass(java.lang.String), rather than this method. Boolean registerAsParallelCapable() Registers the caller as isRegisteredAsParallelCapable() parallel capable. The registration succeeds if and only if all of the following conditions are met: no instance of the caller has been created all of the super classes (except class Object) of the caller are registered as parallel capable Note that once a class loader is registered as parallel capable, there is no way to change it back. Unit resolveClass(c: Class<*>!) Links the specified class. This (misleadingly named) method may be used by a class loader to link a class. If the class c has already been linked, then this method simply returns. Otherwise, the class is linked as described in the "Execution" chapter of The Java Language Specification. Unit setClassAssertionStatus(className: String!, enabled: Boolean) Sets the desired assertion status for the named top-level class in this class loader and any nested classes contained therein. This setting takes precedence over the class loader's default assertion status, and over any applicable per-package default. This method has no effect if the named class has already been initialized. (Once a class is initialized, its assertion status cannot change.) If the named class is not a top-level class, this invocation will have no effect on the actual assertion status of any class. Android-note: AssertionStatuses are unsupported. This method is a no-op. Unit setDefaultAssertionStatus(enabled: Boolean) Sets the default assertion status for this class loader. This setting determines whether classes loaded by this class loader and initialized in the future will have assertions enabled or disabled by default. This setting may be overridden on a per-package or per-class basis by invoking setPackageAssertionStatus(java.lang.String,boolean) or setClassAssertionStatus(java.lang.String,boolean). Android-note: AssertionStatuses are unsupported. This method is a no-op. Unit setPackageAssertionStatus(packageName: String!, enabled: Boolean) Sets the package default assertion status for the named package. The package default assertion status determines the assertion status for classes initialized in the future that belong to the named package or any of its "subpackages". A subpackage of a package named p is any package whose name begins with "p.". For example, javax.swing.text is a subpackage of javax.swing, and both java.util and java.lang.reflect are subpackages of java. In the event that multiple package defaults apply to a given class, the package default pertaining to the most specific package takes precedence over the others. For example, if javax.lang and javax.lang.reflect both have package defaults associated with them, the latter package default applies to classes in javax.lang.reflect. Package defaults take precedence over the class loader's default assertion status, and may be overridden on a per-class basis by invoking setClassAssertionStatus(java.lang.String,boolean). Android-note: AssertionStatuses are unsupported. This method is a no-op. Unit setSigners(c: Class<*>!, signers: Array<Any!>!) Sets the signers of a class. This should be invoked after defining a class.
From class BaseDexClassLoader Class<*>! findClass(name: String!) String! findLibrary(name: String!) URL! findResource(name: String!) Enumeration<URL!>! findResources(name: String!) Package! getPackage(name: 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. String toString()

Public constructors

DexClassLoader

Added in API level 3

DexClassLoader(
    dexPath: String!, 
    optimizedDirectory: String!, 
    librarySearchPath: String!, 
    parent: ClassLoader!)

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	String!: the list of jar/apk files containing classes and resources, delimited by File.pathSeparator, which defaults to ":" on Android
optimizedDirectory	String!: 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