@Test
    public void testIsSimilar() {
        BoundingSphere bs1 = new BoundingSphere(0f, new Vector3f(3f, 4f, 5f));
        BoundingSphere bs2 = new BoundingSphere(0.1f, new Vector3f(3f, 4f, 5f));

        BoundingSphere bs3 = new BoundingSphere(1f, new Vector3f(3f, 4f, 2f));
        BoundingSphere bs4 = new BoundingSphere(1f, new Vector3f(3f, 3.9f, 2f));

        BoundingSphere bs5 = new BoundingSphere(2f, new Vector3f(4f, 5f, 6f));
        BoundingSphere bs6 = (BoundingSphere) bs5.clone();
        bs6.setCheckPlane(1);

        Assert.assertFalse(bs1.isSimilar(bs2, 0.09999f));
        Assert.assertTrue(bs1.isSimilar(bs2, 0.10001f));

        Assert.assertFalse(bs3.isSimilar(bs4, 0.09999f));
        Assert.assertTrue(bs3.isSimilar(bs4, 0.10001f));

        Assert.assertTrue(bs5.isSimilar(bs6, 0f)); // check planes are ignored
    }
Verify that isSimilar() behaves as expected.
jme3-core/src/test/java/com/jme3/bounding/TestBoundingSphere.java