Horrendous performance & large heap footprint of Java 8 constructor reference?

by

In the first case (ArrayList::new) you are using the constructor which takes an initial capacity argument, in the second case you are not. A large initial capacity (index in your code) causes a large Object[] to be allocated, resulting in your OutOfMemoryErrors.

Here are the two constructors’ current implementations:

public ArrayList(int initialCapacity) {
    if (initialCapacity > 0) {
        this.elementData = new Object[initialCapacity];
    } else if (initialCapacity == 0) {
        this.elementData = EMPTY_ELEMENTDATA;
    } else {
        throw new IllegalArgumentException("Illegal Capacity: "+
                                           initialCapacity);
    }
}
public ArrayList() {
    this.elementData = DEFAULTCAPACITY_EMPTY_ELEMENTDATA;
}

Something similar happens in HashSet, except the array is not allocated until add is called.

More Related Contents:

  1. Comparator.reversed() does not compile using lambda
  2. What is the equivalent lambda expression for System.out::println
  3. Is method reference caching a good idea in Java 8?
  4. Java 8: Difference between method reference Bound Receiver and UnBound Receiver
  5. java.lang.NullPointerException is thrown using a method-reference but not a lambda expression
  6. Instance Method Reference and Lambda Parameters
  7. What’s the difference between instance method reference types in Java 8?
  8. What does “an Arbitrary Object of a Particular Type” mean in java 8?
  9. Java 8 chained method reference?
  10. Why can method reference use non-final variables?
  11. Static context cannot access non-static in Collectors
  12. Old JaxB and JDK8 Metaspace OutOfMemory Issue
  13. Please Explain Java 8 Method Reference to instance Method using class name
  14. Difference between method reference Bound Receiver and Unbound Receiver
  15. Reference to methods with different parameters in Java8
  16. Is it unnecessary to put super() in constructor?
  17. Using Java 8’s Optional with Stream::flatMap
  18. Calling method from constructor
  19. Java 8’s streams: why parallel stream is slower?
  20. Optional orElse Optional in Java
  21. Transform Java Future into a CompletableFuture
  22. JavaFX on Linux is showing a “Graphics Device initialization failed for : es2, sw”
  23. How do I create a Stream of regex matches?
  24. How to calculate the number of days in a period?
  25. Why use Optional.of over Optional.ofNullable?
  26. Java: Unable to create new native thread
  27. Java 8 Lambda Expression Within REST Service not working
  28. Can a java lambda have more than 1 parameter?
  29. Get original pattern String given a JDK 8 DateTimeFormatter?
  30. Why does a Java Lambda which throws a Runtime Exception require brackets?

Leave a Comment