stack overflow & null pointer exceptions

[Godmar Back <gback@cs.utah.edu>]

 Hi,

it appears that gcj does not yet implement stack overflow errors properly:
the following program segfaults.  

Apropos segfaulting: it also appears as though NullPointerExceptions aren't
properly caught (?).  See the second test case.

	- Godmar


// Overflow.java
/**
 * Check that stack overflows are handled properly in main thread and
 * other threads.
 *
 * @author Godmar Back <gback@cs.utah.edu>
 */
public class Overflow extends Thread
{
    public void run() {
        try {
            recurse();
        } catch (StackOverflowError e) {
            System.out.println("Success.");
        }
    }

    void recurse() {
        recurse();
    }

    public static void main(String av[]) throws Exception
    {
        Overflow o = new Overflow();
        o.run();        // check for main thread

        o.start();      // check for other thread
        o.join();
    }
}

/* Expected Output:
Success.
Success.
*/


// NullPointerTest.java
/*
 * test that caught null pointers exceptions in finalizers work correctly
 * and that local variables are accessible in null pointer exception handlers.
 */
import java.io.*;

public class NullPointerTest {

    static String s;

    public static void main(String[] args) {
          System.out.println(tryfinally() + s);
    }

    public static String tryfinally() {
        String yuck = null;
        String local_s = null;

        try {
            return "This is ";
        } finally {
            try {
                local_s = "Perfect";
                /* trigger null pointer exception */
                String x = yuck.toLowerCase();
            } catch (Exception _) {
                /* 
                 * when the null pointer exception is caught, we must still
                 * be able to access local_s.
                 * Our return address for the finally clause must also still
                 * be intact.
                 */
                s = local_s;
            }
        }
    }
}


/* Expected Output:
This is Perfect
*/