java 的程序集合,会节省你很多时间的,有两个包.

				import java.lang.ref.*; 
				public class MyReference extends SoftReference {
					public MyReference( Object referent ) {
						super( referent ); 
					}
					public MyReference( Object referent, ReferenceQueue q ) {
						super( referent, q ); 
					}
					public String toString() {
						return String.valueOf(get());
					}
				}