[Demonstration 1]

[Buggy Method]
@Override
public byte[] transform(final ClassLoader loader, final String className, final Class<?> classBeingRedefined, final ProtectionDomain protectionDomain, final byte[] classfileBuffer) throws IllegalClassFormatException {
    if (skip(loader, className)) {
        return null;
    }
    try {
        return instrumenter.instrument(classfileBuffer, className);
    } catch (final IOException e) {
        final IllegalClassFormatException ex = new IllegalClassFormatException(e.getMessage());
        ex.initCause(ex);
        throw ex;
    }
}

[Buggy Hunk]
ex.initCause(ex);

[Patch]
ex.initCause(e);

[Demonstration 2]

[Buggy Method]
@Override
public List<AuctionField> getAuctionFieldsById(long sellerId, long itemId) {
    return allegro.get(sellerId).getAuctionFields(itemId);
}

[Buggy Hunk]
return allegro.get(sellerId).getAuctionFields(itemId);

[Patch]
return allegro.get(sellerId).loginIfNeeded().getAuctionFields(itemId);

[Demonstration 3]

[Buggy Method]
@Override
public byte[] transform(ClassLoader loader, String className, Class<?> classBeingRedefined, ProtectionDomain protectionDomain, byte[] classfileBuffer) throws IllegalClassFormatException {
    try {
        return className.equals(XNET_PROTOCOL) ? doClass(className, classBeingRedefined, classfileBuffer) : classfileBuffer;
    } catch (Throwable err) {
        err.printStackTrace();
        return classfileBuffer;
    }
}

[Buggy Hunk]
return className.equals(XNET_PROTOCOL) ? doClass(className, classBeingRedefined, classfileBuffer) : classfileBuffer;

[Patch]
return className!=null && className.equals(XNET_PROTOCOL) ? doClass(className, classBeingRedefined, classfileBuffer) : classfileBuffer;