Confirm code is correct - crossover methods in Java
It's difficult to just look at, but a few things jump out. More improvements than bugs:


For single point crossover using System.arraycopy() would be much more reliable. For example:

System.arraycopy(parent1Genes, 0, childGenes, 0, xoverPoint);
System.arraycopy(parent2Genes, xoverPoint, childGenes, xoverPoint, geneSize-xoverPoint);

You could use the same method for two point, but it would be slightly more complex.
In Uniform crossover you can use rand.nextBoolean(), which returns true or false, instead of  comparing the float.