if(Boolean_expression 1) {
   // Executes when the Boolean expression 1 is true
   if(Boolean_expression 2) {
      // Executes when the Boolean expression 2 is true
   }
}

public class Test {

   public static void main(String args[]) {
      int x = 30;
      int y = 10;

      if( x == 30 ) {
         if( y == 10 ) {
            System.out.print("X = 30 and Y = 10");
         }
      }
   }
}

X = 30 and Y = 10