System.identityHashCode(Object x)
import java.io.File; public class Main { public static void main(String[] argv) throws Exception { File file1 = new File("a"); File file2 = new File("a"); File file3 = new File("b"); int ihc1 = System.identityHashCode(file1); System.out.println(ihc1); int ihc2 = System.identityHashCode(file2); System.out.println(ihc2); int ihc3 = System.identityHashCode(file3); System.out.println(ihc3); } }