java - Using parameterized type to determine type -

i going throught link

java generic class - determine type

i tried program.

package my;  import java.lang.reflect.parameterizedtype; import java.lang.reflect.type;  public class generictypeidentification {      public static void main( string args[] ) {         node<integer> obj = new generictypeidentification().new subnode<integer>( 1 );         parameterizedtype parameterizedtype = ( parameterizedtype ) obj.getclass().getgenericsuperclass();         type clazz = parameterizedtype.getactualtypearguments()[0];         if ( clazz == integer.class ) {             system.out.println( 1 );         }         else {             system.out.println( 2 );         }     }      class node<t> {          private final t value;          public node( t val ) {             this.value = val;         }          public t evaluate() {             return value;         };      }      class subnode<t> extends node<t> {          private final t value;          public subnode( t val ) {             super( val );             value = val;         }          @override         public t evaluate() {             return value;         };     } } 

my understanding should printh output 1 prints 2. please me in understanding this. thanks.

a trick works used in google guice's typeliteral. in constructor of subclass of generic class, do have access parent's generic "instantiation", @ runtime... because generic type information has been retained inheritance purposes @ compile-time. example usage:

typeliteral<myclass> test = new typeliteral<myclass>() {}; // notice {} build anon. subclass system.err.println(test.gettype()); // outputs "myclass" 

this not work without using subclass-of-a-generic, due type erasure; , overkill applications.