Does Java have lazy evaluation?

Question

I know that Java has smart/lazy evaluation in this case:

public boolean isTrue() {
    boolean a = false;
    boolean b = true;
    return b || (a &&         


        

Answer 1

SE8 (JDK1.8) has introduced Lambda expressions, which can make lazy evaluations more transparent. Consider the statement in the main method of the following code:

@FunctionalInterface
public interface Lazy {
   T value();
}

class Test {
   private String veryLongMethod() {
      //Very long computation
      return "";
   }

   public static  T coalesce(T primary, Lazy secondary) {
      return primary != null? primary : secondary.value();
   }

   public static void main(String[] argv) {
      String result = coalesce(argv[0], ()->veryLongMethod());
   }
}

The called function coalesce returns the first given non-null value (as in SQL). The second parameter in its call is a Lambda expression. The method veryLongMethod() will be called only when argv[0] == null. The only payload in this case is inserting ()-> before the value to be lazily evaluated on demand.