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+package com.op1.util;%0A%0A/**%0A * Input argument validation methods, like guava's Preconditions, but just to remain dependency free.%0A */%0Apublic class Check %7B%0A%0A    public static void notNull(Object o, String message) %7B%0A        if (o == null) %7B%0A            throw new IllegalArgumentException(message);%0A        %7D%0A    %7D%0A%0A    public static void that(boolean b, String message) %7B%0A        if (!b) %7B%0A            throw new IllegalArgumentException(message);%0A        %7D%0A    %7D%0A%0A    public static void support(boolean b, String message) %7B%0A        if (!b) %7B%0A            throw new UnsupportedOperationException(message);%0A        %7D%0A    %7D%0A%7D%0A

Create Check.java