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6864003: Modify JVM_FindClassFromBootLoader to return null if class not found

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JVM_FindClassFromBootLoader returns null if class not found

Reviewed-by: acorn, alanb, dholmes
This commit is contained in:
Mandy Chung 2009-07-27 09:06:22 -07:00
parent fea09e9cd0
commit 3c30eafbb5
2 changed files with 51 additions and 46 deletions
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88
hotspot/src/share/vm/prims/jvm.cpp
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@ -638,11 +638,54 @@ JVM_ENTRY(void, JVM_ResolveClass(JNIEnv* env, jclass cls))
if (PrintJVMWarnings) warning("JVM_ResolveClass not implemented");
JVM_END
// Common implementation for JVM_FindClassFromBootLoader and
// JVM_FindClassFromLoader
static jclass jvm_find_class_from_class_loader(JNIEnv* env, const char* name,
jboolean init, jobject loader,
jboolean throwError, TRAPS) {
// Returns a class loaded by the bootstrap class loader; or null
// if not found. ClassNotFoundException is not thrown.
//
// Rationale behind JVM_FindClassFromBootLoader
// a> JVM_FindClassFromClassLoader was never exported in the export tables.
// b> because of (a) java.dll has a direct dependecy on the unexported
// private symbol "_JVM_FindClassFromClassLoader@20".
// c> the launcher cannot use the private symbol as it dynamically opens
// the entry point, so if something changes, the launcher will fail
// unexpectedly at runtime, it is safest for the launcher to dlopen a
// stable exported interface.
// d> re-exporting JVM_FindClassFromClassLoader as public, will cause its
// signature to change from _JVM_FindClassFromClassLoader@20 to
// JVM_FindClassFromClassLoader and will not be backward compatible
// with older JDKs.
// Thus a public/stable exported entry point is the right solution,
// public here means public in linker semantics, and is exported only
// to the JDK, and is not intended to be a public API.
JVM_ENTRY(jclass, JVM_FindClassFromBootLoader(JNIEnv* env,
const char* name))
JVMWrapper2("JVM_FindClassFromBootLoader %s", name);
// Java libraries should ensure that name is never null...
if (name == NULL || (int)strlen(name) > symbolOopDesc::max_length()) {
// It's impossible to create this class; the name cannot fit
// into the constant pool.
return NULL;
}
symbolHandle h_name = oopFactory::new_symbol_handle(name, CHECK_NULL);
klassOop k = SystemDictionary::resolve_or_null(h_name, CHECK_NULL);
if (k == NULL) {
return NULL;
}
if (TraceClassResolution) {
trace_class_resolution(k);
}
return (jclass) JNIHandles::make_local(env, Klass::cast(k)->java_mirror());
JVM_END
JVM_ENTRY(jclass, JVM_FindClassFromClassLoader(JNIEnv* env, const char* name,
jboolean init, jobject loader,
jboolean throwError))
JVMWrapper3("JVM_FindClassFromClassLoader %s throw %s", name,
throwError ? "error" : "exception");
// Java libraries should ensure that name is never null...
if (name == NULL || (int)strlen(name) > symbolOopDesc::max_length()) {
// It's impossible to create this class; the name cannot fit
@ -662,40 +705,6 @@ static jclass jvm_find_class_from_class_loader(JNIEnv* env, const char* name,
trace_class_resolution(java_lang_Class::as_klassOop(JNIHandles::resolve_non_null(result)));
}
return result;
}
// Rationale behind JVM_FindClassFromBootLoader
// a> JVM_FindClassFromClassLoader was never exported in the export tables.
// b> because of (a) java.dll has a direct dependecy on the unexported
// private symbol "_JVM_FindClassFromClassLoader@20".
// c> the launcher cannot use the private symbol as it dynamically opens
// the entry point, so if something changes, the launcher will fail
// unexpectedly at runtime, it is safest for the launcher to dlopen a
// stable exported interface.
// d> re-exporting JVM_FindClassFromClassLoader as public, will cause its
// signature to change from _JVM_FindClassFromClassLoader@20 to
// JVM_FindClassFromClassLoader and will not be backward compatible
// with older JDKs.
// Thus a public/stable exported entry point is the right solution,
// public here means public in linker semantics, and is exported only
// to the JDK, and is not intended to be a public API.
JVM_ENTRY(jclass, JVM_FindClassFromBootLoader(JNIEnv* env,
const char* name,
jboolean throwError))
JVMWrapper3("JVM_FindClassFromBootLoader %s throw %s", name,
throwError ? "error" : "exception");
return jvm_find_class_from_class_loader(env, name, JNI_FALSE,
(jobject)NULL, throwError, THREAD);
JVM_END
JVM_ENTRY(jclass, JVM_FindClassFromClassLoader(JNIEnv* env, const char* name,
jboolean init, jobject loader,
jboolean throwError))
JVMWrapper3("JVM_FindClassFromClassLoader %s throw %s", name,
throwError ? "error" : "exception");
return jvm_find_class_from_class_loader(env, name, init, loader,
throwError, THREAD);
JVM_END
@ -3919,6 +3928,7 @@ jclass find_class_from_class_loader(JNIEnv* env, symbolHandle name, jboolean ini
// The Java level wrapper will perform the necessary security check allowing
// us to pass the NULL as the initiating class loader.
klassOop klass = SystemDictionary::resolve_or_fail(name, loader, protection_domain, throwError != 0, CHECK_NULL);
KlassHandle klass_handle(THREAD, klass);
// Check if we should initialize the class
if (init && klass_handle->oop_is_instance()) {