/**
* Tests whether aObject is null.
*
* @param aObject the Object to be tested for nullity
*
* @return true if aObject is null, false otherwise
*/
public final static boolean isNull( final Object aObject ){
return areIdentical( aObject, null );
}

/**
* Tests whether aObject is non-null.
*
* @param aObject the Object to be tested for non-nullity
*
* @return false if aObject is null, true otherwise
*/
public final static boolean notNull( final Object aObject ){
return not( isNull( aObject ) );
}

For Stefan:
(1) a null-safe equals() method which depends upon (2) areIdentical() which hides == so that I don’t use single = by mistake.

I have these in an Object utility class I call ObjectUtil.

/**
* Tests any two Objects ( including the case of two nulls ) for equality.
*
* @param o1 the first Object to be tested
* @param o2 the second Object to be tested
*
* @return true if the two objects are equal, false otherwise
*/
public final static boolean areEqual( final Object o1, final Object o2 ){
return areIdentical( o1, o2 ) || ( notNull( o1 ) && o1.equals( o2 ) );
}

/**
* Tests any two Objects for identity.
*
* @param o1 the first Object to be tested
* @param o2 the second Object to be tested
*
* @return true if the two objects are identical, false otherwise
*/
public final static boolean areIdentical( final Object o1, final Object o2 ){
return ( o1 == o2 );
}