Question

Is there a limit to the number of elements a Java array can contain? If so, what is it?

Answer 1

Using

OpenJDK 64-Bit Server VM (build 15.0.2+7, mixed mode, sharing)

… on MacOS, the answer seems to be Integer.MAX_VALUE - 2. Once you go beyond that:

cat > Foo.java << "END"
public class Foo {
  public static void main(String[] args) {
    boolean[] array = new boolean[Integer.MAX_VALUE - 1]; // too big
  }
}
END
java -Xmx4g Foo.java

… you get:

Exception in thread "main" java.lang.OutOfMemoryError:
  Requested array size exceeds VM limit