Why Gigster?
  • Top talentTop talent
  • Managed serviceManaged service
  • Liquid workforceLiquid workforce
  • Scalable infrastructureScalable infrastructure
  • Enterprise securityEnterprise security
Why Gigster?
  • Top talentTop talent
  • Managed serviceManaged service
  • Liquid workforceLiquid workforce
  • Scalable infrastructureScalable infrastructure
  • Enterprise securityEnterprise security

Java Interview Question

Use this intermediate question and answer to prepare for your next Java interview.

Why won't the following code sample compile? How can you correct it?

class A {
  public static void main(String...args) {
    List<String> ls = new ArrayList<String>();
    t1(ls);
  }

  public void t1(List<Object> lo) { }
}


This will raise a compilation error. It is incorrect to pass a List<String> to a method accepting List<Object>. A List<Object> can accept Strings, but t1 can only accept List<Object>.

Either ls should be changed to List<Object>, or lo should be made Generic: List<? extends Object> lo

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