/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		// what happens if null is used in String concatenation
		String verb = null;
		String text = "cat " + verb;
		System.out.println(text);
 
		text = "cat " + verb + " an animal";
		System.out.println(text);
	}
}

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