Why does a null value appear in string output?
java, null, string, string-concatenation
Solution
You are attempting to concatenate a value to `null`. This is governed by "String Conversion", which occurs when one operand is a `String`, and that is covered by the JLS, Section 5.1.11:
Now only reference values need to be considered:
- If the reference is null, it is converted to the string "null" (four ASCII characters n, u, l, l).
Problem
When I execute the following code the output is "nullHelloWorld". How does Java treat null? ``` 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 { String str=null; str+="Hello World"; System.out.println(str); } } ```