IgnoreExternalNotNull.java

import org.jetbrains.annotations.NotNull;

import java.lang.Override;
import java.lang.UnsupportedOperationException;
import java.util.Date;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;

abstract class Demo6Impl implements Condition {
  @Override
  public boolean awaitUntil(Date deadline) {
            /* This is considered to be an error in Eclipse: The second parameter is not annotated in the JDK but
             * only through the external annotations in IntelliJ. Thus, Eclipse is complaining:
             * Illegal redefinition of parameter unit, inherited method from ExecutorService does not constrain this parameter
             */
    return false;
  }
}

abstract class LockImpl implements Lock {
  @Override
  public Condition newCondition() { // overriding external notnull here
    return null;
  }
}