title: What is the best runtime exception to use when mandatory input is missing
body: <p>I have service, a simple class that need to take input and run some business logic. Before executing this service, the user must set all the data. In general, it look like this:</p>
  
  <pre><code>public class TestService extends InnerServiceBase {
  
      /**
       * Mandatory input 
       */
      private  Object inputObj;
  
      @Override
      protected ErrorCode executeImpl() {
          //Some business logic on inputObj
          return null;
      }
  
      public void setInputObj(Object inputObj) {
          this.inputObj = inputObj;
      }
  } 
  </code></pre>
  
  <p>What is the best runtime exception to throw in case the <code>inputObj</code> is null ?</p>