Range Check. Definitely not patented or copyrighted by Oracle. (https://majadhondt.wordpress.com/2012/05/16/googles-9-lines/)

JosefsProprietaryRangeCheckPatentPending.java

// This is _definitely_ my own implementation of rangeCheck and no one else's. Definitely not infringing on anything.

private static void rangeCheck(int arrayLen, int fromIndex, int toIndex) {
    if (fromIndex > toIndex)
        throw new IllegalArgumentException("fromIndex(" + fromIndex +") > toIndex(" + toIndex+")");
    if (fromIndex < 0) 
        throw new ArrayIndexOutOfBoundsException(fromIndex);
    if (toIndex > arrayLen) 
        throw new ArrayIndexOutOfBoundsException(toIndex);
}