Behavior change since 6u14. The GC decides not to clear the SoftReference but
an object in the reference chain of that SoftReference is being cleared.

Below is the test program showing the problem. Specifically,
o2 is only reachable via s2 (SoftReference) and s2 is not cleared
and thus w2.get() should return non-null.

import java.lang.ref.*;
import java.util.*;

public class RefCompliance {
    
    RefCompliance () {
    }

    public static void test() {

        int[] o1 = new int[10];

        WeakReference w1 = new WeakReference(o1);
        SoftReference s1 = new SoftReference(w1);

        int[] o2 = new int[10];

        WeakReference w2 = new WeakReference(o2);
        SoftReference s2 = new SoftReference(w2);

        int[] o3 = new int[10];

        WeakReference w3 = new WeakReference(o3);

        o1 = null;
        o2 = null;
        o3 = null;
        w2 = null;

        // Scrub stack because of conservative collector
        int[] dummy1 = new int[10];
        int[] dummy2 = new int[10];

        System.gc();

        int res1;

        w2 = (WeakReference)s2.get();
        if (w1 == s1.get()) {
            res1 = 0;
            if (w1.get() == null) {
                res1 += 100;
            }
            if (w2.get() == null) {
                res1 += 10;
            }
            if (w3.get() == null) {
                res1 += 1;
            }
        } else {
            res1 = -1;
        }

        if (res1 == 101) {
            System.err.println("JDK1.2");
        } else if (res1 == 111) {
            System.err.println("weakest link on strongest chain");
        } else if (res1 == 001) {
            System.err.println("API spec");
        } else {
            System.err.println("unknown: result " + res1);
        }
    }

    public static void main(String[] args) {
        test();
        test();
        test();
        test();
        test();
    }
}

$ /java/re/jdk/6u13/latest/binaries/solaris-i586/bin/java RefCompliance
JDK1.2
JDK1.2
JDK1.2
JDK1.2
JDK1.2

$ /java/re/jdk/6u14/latest/binaries/solaris-i586/bin/java RefCompliance
weakest link on strongest chain
weakest link on strongest chain
weakest link on strongest chain
weakest link on strongest chain
weakest link on strongest chain