Some Pre conditions/assertions that one would encounter in everyday programming

PreCondition.java

public class PreCondition {
	
	public static <T> void  checkNull(final T  t, final String errorMsg){
		if(t==null){
			throw new IllegalArgumentException(errorMsg);
		}
	}
	public static void  checkEmptyString(final String str, final String errorMsg){
		if(!Strings.hasText(str)){
			throw new IllegalArgumentException(errorMsg);
		}
	}
	public static <T> void checkEmptyCollection(final Collection<T> collection,final String errorMsg){
		if(collection == null || collection.isEmpty()){
			throw new IllegalArgumentException(errorMsg);
		}
	}
	
	public static void checkExpression(final boolean expression ,final String errorMsg){
		if(expression){
			throw new IllegalArgumentException(errorMsg);
		}
	}
}