Name: akC45999 Date: 03/13/98



The description of java.lang.Class.forName() reads:

Given the fully-qualified name for a class or interface, this method attempts
to locate, load and link the class. If it succeeds, returns the Class object
representing the class. If it fails, the method throws a ClassNotFoundException.

But in the JDK1.1 ... JDK1.2 the method throws various subclasses of LinkageError
instead, depending on actual reason of linkage failure. Though such behavior
may be considered more useful than the specified, it violates the specification
and must be fixed, unless the specification changes.

See also RFE 4118967 on possible specification change, and "reverse" bug
4112525 (runtime throws ClassNotFoundException while a LinkageError must be thrown).

The following test illustrates the bug.

Save 3 files in a working directory and run the script "runtest":

novo64% which java
/export/ld14/java/dest/jdk1.1.4/solaris/bin/java
novo64% runtest
javac ClassForName.java
jasm aClass.jasm
exception while loading test: java.lang.VerifyError: aClass

novo64% which java
/export/ld14/java/dest/jdk1.1.6/solaris/bin/java
novo64% java -verify ClassForName
exception while loading test: java.lang.VerifyError

novo64% which java
/export/ld14/java/dest/jdk1.2/solaris/bin/java
java -verify ClassForName
exception while loading test: java.lang.VerifyError: (class: aClass, method: <clinit> signature: ()V) Illegal local variable number

============================================================ ClassForName.java
import java.io.PrintStream;


public class ClassForName {

  public static void main(String args[]) {
try {
Class executeClass = Class.forName("aClass");
} catch (Throwable e) {
System.out.println("exception while loading test: " + e);
        return;
}

  }

}

============================================================ aClass.jasm
class aClass {

public static Method "<clinit>":"()V"
stack 0 locals 0
{
aload_0; // error because maxstack==maxlocals==0
return;
}

}

========================================================== runtest
#!/bin/sh

rm -rf *class

CLASSPATH=.
export CLASSPATH

cmd="javac ClassForName.java"
echo $cmd; eval $cmd
cmd="jasm aClass.jasm"
echo $cmd; eval $cmd

java -verify ClassForName

============================================================

======================================================================