Method from java.lang.ClassLoader Detail: |
void addClass(Class c) {
classes.addElement(c);
}
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public void clearAssertionStatus() {
/*
* Whether or not "Java assertion maps" are initialized, set
* them to empty maps, effectively ignoring any present settings.
*/
synchronized (assertionLock) {
classAssertionStatus = new HashMap< >();
packageAssertionStatus = new HashMap< >();
defaultAssertionStatus = false;
}
}
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."
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protected final Class<?> defineClass(byte[] b,
int off,
int len) throws ClassFormatError {
return defineClass(null, b, off, len, null);
} Deprecated! Replaced - by byte[], int, int)
byte[], int, 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. |
protected final Class<?> defineClass(String name,
ByteBuffer b,
ProtectionDomain protectionDomain) throws ClassFormatError {
int len = b.remaining();
// Use byte[] if not a direct ByteBufer:
if (!b.isDirect()) {
if (b.hasArray()) {
return defineClass(name, b.array(),
b.position() + b.arrayOffset(), len,
protectionDomain);
} else {
// no array, or read-only array
byte[] tb = new byte[len];
b.get(tb); // get bytes out of byte buffer.
return defineClass(name, tb, 0, len, protectionDomain);
}
}
protectionDomain = preDefineClass(name, protectionDomain);
Class c = null;
String source = defineClassSourceLocation(protectionDomain);
try {
c = defineClass2(name, b, b.position(), len, protectionDomain,
source);
} catch (ClassFormatError cfe) {
byte[] tb = new byte[len];
b.get(tb); // get bytes out of byte buffer.
c = defineTransformedClass(name, tb, 0, len, protectionDomain, cfe,
source);
}
postDefineClass(c, protectionDomain);
return c;
}
Converts a ByteBuffer
into an instance of class Class,
with an optional ProtectionDomain. If the domain is
null, then a default domain will be assigned to the class as
specified in the documentation for #defineClass(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, and the restrictions on class names
are identical to those specified in the documentation for #defineClass(String, byte[], int, int, 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 byte[], int, int, ProtectionDomain)
cl.defineClass (name, temp, 0,
temp.length, pd);
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protected final Class<?> defineClass(String name,
byte[] b,
int off,
int len) throws ClassFormatError {
return defineClass(name, b, off, len, null);
}
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 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. |
protected final Class<?> defineClass(String name,
byte[] b,
int off,
int len,
ProtectionDomain protectionDomain) throws ClassFormatError {
protectionDomain = preDefineClass(name, protectionDomain);
Class c = null;
String source = defineClassSourceLocation(protectionDomain);
try {
c = defineClass1(name, b, off, len, protectionDomain, source);
} catch (ClassFormatError cfe) {
c = defineTransformedClass(name, b, off, len, protectionDomain, cfe,
source);
}
postDefineClass(c, protectionDomain);
return c;
}
Converts an array of bytes into an instance of class Class,
with an optional ProtectionDomain. If the domain is
null, then a default domain will be assigned to the class as
specified in the documentation for #defineClass(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.
The specified name cannot begin with "java.", since
all classes in the "java.* packages can only be defined by the
bootstrap class loader. If name is not null, it
must be equal to the binary name of the class
specified by the byte array "b", otherwise a NoClassDefFoundError will be thrown. |
protected Package definePackage(String name,
String specTitle,
String specVersion,
String specVendor,
String implTitle,
String implVersion,
String implVendor,
URL sealBase) throws IllegalArgumentException {
synchronized (packages) {
Package pkg = getPackage(name);
if (pkg != null) {
throw new IllegalArgumentException(name);
}
pkg = new Package(name, specTitle, specVersion, specVendor,
implTitle, implVersion, implVendor,
sealBase, this);
packages.put(name, pkg);
return pkg;
}
}
Defines a package by name in this ClassLoader. This allows
class loaders to define the packages for their classes. Packages must
be created before the class is defined, and package names must be
unique within a class loader and cannot be redefined or changed once
created. |
boolean desiredAssertionStatus(String className) {
synchronized (assertionLock) {
// assert classAssertionStatus != null;
// assert packageAssertionStatus != null;
// Check for a class entry
Boolean result = classAssertionStatus.get(className);
if (result != null)
return result.booleanValue();
// Check for most specific package entry
int dotIndex = className.lastIndexOf(".");
if (dotIndex < 0) { // default package
result = packageAssertionStatus.get(null);
if (result != null)
return result.booleanValue();
}
while(dotIndex > 0) {
className = className.substring(0, dotIndex);
result = packageAssertionStatus.get(className);
if (result != null)
return result.booleanValue();
dotIndex = className.lastIndexOf(".", dotIndex-1);
}
// Return the classloader default
return defaultAssertionStatus;
}
}
Returns the assertion status that would be assigned to the specified
class if it were to be initialized at the time this method is invoked.
If the named class has had its assertion status set, the most recent
setting will be returned; otherwise, if any package default assertion
status pertains to this class, the most recent setting for the most
specific pertinent package default assertion status is returned;
otherwise, this class loader's default assertion status is returned.
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protected Class<?> findClass(String name) throws ClassNotFoundException {
throw new ClassNotFoundException(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. The default implementation
throws a ClassNotFoundException. |
protected String findLibrary(String libname) {
return null;
}
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. |
protected final Class<?> findLoadedClass(String name) {
if (!checkName(name))
return null;
return findLoadedClass0(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. Otherwise
null is returned. |
static long findNative(ClassLoader loader,
String name) {
Vector< NativeLibrary > libs =
loader != null ? loader.nativeLibraries : systemNativeLibraries;
synchronized (libs) {
int size = libs.size();
for (int i = 0; i < size; i++) {
NativeLibrary lib = libs.elementAt(i);
long entry = lib.find(name);
if (entry != 0)
return entry;
}
}
return 0;
}
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protected URL findResource(String name) {
return null;
}
Finds the resource with the given name. Class loader implementations
should override this method to specify where to find resources. |
protected Enumeration<URL> findResources(String name) throws IOException {
return java.util.Collections.emptyEnumeration();
}
Returns an enumeration of URL objects
representing all the resources with the given name. Class loader
implementations should override this method to specify where to load
resources from. |
protected final Class<?> findSystemClass(String name) throws ClassNotFoundException {
ClassLoader system = getSystemClassLoader();
if (system == null) {
if (!checkName(name))
throw new ClassNotFoundException(name);
Class cls = findBootstrapClass(name);
if (cls == null) {
throw new ClassNotFoundException(name);
}
return cls;
}
return system.loadClass(name);
}
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(String) . |
static URLClassPath getBootstrapClassPath() {
return sun.misc.Launcher.getBootstrapClassPath();
}
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static ClassLoader getCallerClassLoader() {
// NOTE use of more generic Reflection.getCallerClass()
Class caller = Reflection.getCallerClass(3);
// This can be null if the VM is requesting it
if (caller == null) {
return null;
}
// Circumvent security check since this is package-private
return caller.getClassLoader0();
}
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protected Object getClassLoadingLock(String className) {
Object lock = this;
if (parallelLockMap != null) {
Object newLock = new Object();
lock = parallelLockMap.putIfAbsent(className, newLock);
if (lock == null) {
lock = newLock;
}
}
return lock;
}
Returns the lock object for class loading operations.
For backward compatibility, the default implementation of this method
behaves as follows. If this ClassLoader object is registered as
parallel capable, the method returns a dedicated object associated
with the specified class name. Otherwise, the method returns this
ClassLoader object. |
protected Package getPackage(String name) {
Package pkg;
synchronized (packages) {
pkg = packages.get(name);
}
if (pkg == null) {
if (parent != null) {
pkg = parent.getPackage(name);
} else {
pkg = Package.getSystemPackage(name);
}
if (pkg != null) {
synchronized (packages) {
Package pkg2 = packages.get(name);
if (pkg2 == null) {
packages.put(name, pkg);
} else {
pkg = pkg2;
}
}
}
}
return pkg;
}
Returns a Package that has been defined by this class loader
or any of its ancestors. |
protected Package[] getPackages() {
Map< String, Package > map;
synchronized (packages) {
map = new HashMap< >(packages);
}
Package[] pkgs;
if (parent != null) {
pkgs = parent.getPackages();
} else {
pkgs = Package.getSystemPackages();
}
if (pkgs != null) {
for (int i = 0; i < pkgs.length; i++) {
String pkgName = pkgs[i].getName();
if (map.get(pkgName) == null) {
map.put(pkgName, pkgs[i]);
}
}
}
return map.values().toArray(new Package[map.size()]);
}
Returns all of the Packages defined by this class loader and
its ancestors. |
public final ClassLoader getParent() {
if (parent == null)
return null;
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
ClassLoader ccl = getCallerClassLoader();
if (ccl != null && !isAncestor(ccl)) {
sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION);
}
}
return parent;
}
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.
If a security manager is present, and the invoker's class loader is
not null and is not an ancestor of this class loader, then this
method invokes the security manager's checkPermission method with a RuntimePermission("getClassLoader") permission to verify
access to the parent class loader is permitted. If not, a
SecurityException will be thrown. |
public URL getResource(String name) {
URL url;
if (parent != null) {
url = parent.getResource(name);
} else {
url = getBootstrapResource(name);
}
if (url == null) {
url = findResource(name);
}
return url;
}
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 that
identifies the resource.
This method will first search the parent class loader for the
resource; if the parent is null the path of the class loader
built-in to the virtual machine is searched. That failing, this method
will invoke #findResource(String) to find the resource. |
public InputStream getResourceAsStream(String name) {
URL url = getResource(name);
try {
return url != null ? url.openStream() : null;
} catch (IOException e) {
return null;
}
}
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public Enumeration<URL> getResources(String name) throws IOException {
Enumeration[] tmp = new Enumeration[2];
if (parent != null) {
tmp[0] = parent.getResources(name);
} else {
tmp[0] = getBootstrapResources(name);
}
tmp[1] = findResources(name);
return new CompoundEnumeration< >(tmp);
}
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.
The search order is described in the documentation for #getResource(String) . |
public static ClassLoader getSystemClassLoader() {
initSystemClassLoader();
if (scl == null) {
return null;
}
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
ClassLoader ccl = getCallerClassLoader();
if (ccl != null && ccl != scl && !scl.isAncestor(ccl)) {
sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION);
}
}
return scl;
}
Returns the system class loader for delegation. 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 and sets it
as the context class loader of the invoking Thread.
The default system class loader is an implementation-dependent
instance of this class.
If the system property "java.system.class.loader" is defined
when this method is first invoked then the value of that property is
taken to be the name of a class that will be returned as the system
class loader. The class is loaded using the default system class loader
and must define a public constructor that takes a single parameter of
type ClassLoader which is used as the delegation parent. An
instance is then created using this constructor with the default system
class loader as the parameter. The resulting class loader is defined
to be the system class loader.
If a security manager is present, and the invoker's class loader is
not null and the invoker's class loader is not the same as or
an ancestor of the system class loader, then this method invokes the
security manager's checkPermission method with a RuntimePermission("getClassLoader") permission to verify
access to the system class loader. If not, a
SecurityException will be thrown. |
public static URL getSystemResource(String name) {
ClassLoader system = getSystemClassLoader();
if (system == null) {
return getBootstrapResource(name);
}
return system.getResource(name);
}
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() ). |
public static InputStream getSystemResourceAsStream(String name) {
URL url = getSystemResource(name);
try {
return url != null ? url.openStream() : null;
} catch (IOException e) {
return null;
}
}
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() ). |
public static Enumeration<URL> getSystemResources(String name) throws IOException {
ClassLoader system = getSystemClassLoader();
if (system == null) {
return getBootstrapResources(name);
}
return system.getResources(name);
}
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boolean isAncestor(ClassLoader cl) {
ClassLoader acl = this;
do {
acl = acl.parent;
if (cl == acl) {
return true;
}
} while (acl != null);
return false;
}
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public Class<?> loadClass(String name) throws ClassNotFoundException {
return loadClass(name, false);
}
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protected Class<?> loadClass(String name,
boolean resolve) throws ClassNotFoundException {
synchronized (getClassLoadingLock(name)) {
// First, check if the class has already been loaded
Class c = findLoadedClass(name);
if (c == null) {
long t0 = System.nanoTime();
try {
if (parent != null) {
c = parent.loadClass(name, false);
} else {
c = findBootstrapClassOrNull(name);
}
} catch (ClassNotFoundException e) {
// ClassNotFoundException thrown if class not found
// from the non-null parent class loader
}
if (c == null) {
// If still not found, then invoke findClass in order
// to find the class.
long t1 = System.nanoTime();
c = findClass(name);
// this is the defining class loader; record the stats
sun.misc.PerfCounter.getParentDelegationTime().addTime(t1 - t0);
sun.misc.PerfCounter.getFindClassTime().addElapsedTimeFrom(t1);
sun.misc.PerfCounter.getFindClasses().increment();
}
}
if (resolve) {
resolveClass(c);
}
return c;
}
}
Loads the class with the specified binary name. The
default implementation of this method searches for classes in the
following order:
Invoke #findLoadedClass(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-in to the virtual machine is used, instead.
Invoke the #findClass(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(Class) method on the resulting Class object.
Subclasses of ClassLoader are encouraged to override #findClass(String) , rather than this method.
Unless overridden, this method synchronizes on the result of
getClassLoadingLock method
during the entire class loading process. |
static void loadLibrary(Class fromClass,
String name,
boolean isAbsolute) {
ClassLoader loader =
(fromClass == null) ? null : fromClass.getClassLoader();
if (sys_paths == null) {
usr_paths = initializePath("java.library.path");
sys_paths = initializePath("sun.boot.library.path");
}
if (isAbsolute) {
if (loadLibrary0(fromClass, new File(name))) {
return;
}
throw new UnsatisfiedLinkError("Can't load library: " + name);
}
if (loader != null) {
String libfilename = loader.findLibrary(name);
if (libfilename != null) {
File libfile = new File(libfilename);
if (!libfile.isAbsolute()) {
throw new UnsatisfiedLinkError(
"ClassLoader.findLibrary failed to return an absolute path: " + libfilename);
}
if (loadLibrary0(fromClass, libfile)) {
return;
}
throw new UnsatisfiedLinkError("Can't load " + libfilename);
}
}
for (int i = 0 ; i < sys_paths.length ; i++) {
File libfile = new File(sys_paths[i], System.mapLibraryName(name));
if (loadLibrary0(fromClass, libfile)) {
return;
}
}
if (loader != null) {
for (int i = 0 ; i < usr_paths.length ; i++) {
File libfile = new File(usr_paths[i],
System.mapLibraryName(name));
if (loadLibrary0(fromClass, libfile)) {
return;
}
}
}
// Oops, it failed
throw new UnsatisfiedLinkError("no " + name + " in java.library.path");
}
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protected static boolean registerAsParallelCapable() {
return ParallelLoaders.register(getCaller(1));
}
Registers the caller as parallel capable.
The registration succeeds if and only if all of the following
conditions are met:
1. no instance of the caller has been created
2. 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. |
protected final void resolveClass(Class<?> c) {
resolveClass0(c);
}
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.
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public void setClassAssertionStatus(String className,
boolean enabled) {
synchronized (assertionLock) {
if (classAssertionStatus == null)
initializeJavaAssertionMaps();
classAssertionStatus.put(className, enabled);
}
}
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. |
public void setDefaultAssertionStatus(boolean enabled) {
synchronized (assertionLock) {
if (classAssertionStatus == null)
initializeJavaAssertionMaps();
defaultAssertionStatus = enabled;
}
}
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public void setPackageAssertionStatus(String packageName,
boolean enabled) {
synchronized (assertionLock) {
if (packageAssertionStatus == null)
initializeJavaAssertionMaps();
packageAssertionStatus.put(packageName, enabled);
}
}
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(String, boolean) . |
protected final void setSigners(Class<?> c,
Object[] signers) {
c.setSigners(signers);
}
Sets the signers of a class. This should be invoked after defining a
class. |