/*xml
   <module name="Checker">
     <module name="TreeWalker">
       <module name="UnnecessaryNullCheckWithInstanceOf"/>
     </module>
   </module>
   */
   package com.puppycrawl.tools.checkstyle.checks.coding.unnecessarynullcheckwithinstanceof;
   
  import java.util.ArrayList;
  import java.util.List;
  
  // xdoc section -- start
  public class Example1 {
  
    public void methodWithUnnecessaryNullCheck1(Object obj) {
      // violation below, 'Unnecessary nullity check'
      if (obj != null && obj instanceof String) {
        String str = (String) obj;
      }
      if (obj instanceof String) {
        String str = (String) obj;
      }
      // violation below, 'Unnecessary nullity check'
      boolean isInvalid = obj != null && obj instanceof String;
  
      boolean isValid = obj instanceof String;
    }
    interface Validator {
      boolean validate(Object obj);
    }
    public void anonymousClassImplementation() {
      Validator v = new Validator() {
        @Override
        public boolean validate(Object obj) {
          // violation below, 'Unnecessary nullity check'
          return obj != null && obj instanceof String;
        }
      };
    }
    private final List<Object> objects = new ArrayList<>();
  
    public String basicTernary(Object obj) {
      // violation below, 'Unnecessary nullity check'
      return obj != null && obj instanceof String ? ((String) obj) : "";
    }
  
    public String basicValidTernary(Object obj) {
      return obj instanceof String ? ((String) obj) : "";
    }
    public void methodWithValidNullCheck(Object obj) {
      if (obj != null) {
        CharSequence cs = (CharSequence) obj;
      }
    }
  }
  // xdoc section -- end