How to make the java system release Soft References?

Question

I\'m going to use a SoftReference-based cache (a pretty simple thing by itself). However, I\'ve came across a problem when writing a test for it.

The objective of th

Answer 1

An improvement that will work for more than 2G max memory. It loops until an OutOfMemory error occurs.

@Test
public void shouldNotHoldReferencesToObject() {
    final SoftReference reference = new SoftReference( ... );

    // Sanity check
    assertThat(reference.get(), not(equalTo(null)));

    // Force an OoM
    try {
        final ArrayList allocations = new ArrayList();
        int size;
        while( (size = Math.min(Math.abs((int)Runtime.getRuntime().freeMemory()),Integer.MAX_VALUE))>0 )
            allocations.add( new Object[size] );
    } catch( OutOfMemoryError e ) {
        // great!
    }

    // Verify object has been garbage collected
    assertThat(reference.get(), equalTo(null));

}