I want to replace a entire String with new value using String replaceAll method in Java

java

Solution

Your regular expression can match 0 to all characters. First, it matches the entire string `"Welcome to Java World"`, then it matches the end of the string `""`, replacing both with `"JAVA"`.

To make this work how you expect it, you have a couple options.

String x = "Welcome to Java World";
System.out.println(x.replaceAll(".+","JAVA"));

Notice the + instead of the *, this means 1 or many, so the end won't be matched.

or

String x = "Welcome to Java World";
System.out.println(x.replaceFirst(".*","JAVA"));

This will only replace the entire string with `"JAVA"`, the empty end of the string won't be replaced.

Problem

Original source