Following is my code:
class program{
public static void main(String[]args){
String str = new String("I like Java ");
str.concat("the most");
str.toUpperCase();
str.replace("LIKE","LOVE");
System.out.println(str);
}
}
As I expect the output should be as:
I LOVE JAVA THE MOST
But, It isn't showing an error but also not showing the expected output...Instead it is only showing the original string:
Am I missing something or may be is it something else?
The String class is immutable. This means that every method does not change the original String instance, but it creates a new object and returns it, but you are not saving their reference. You could do:
String str = "I like Java";
str = str.concat("the most");
str = str.toUpperCase();
str = str.replace("LIKE","LOVE");
Or even better:
String str = "I like Java"
.concat("the most")
.toUpperCase()
.replace("LIKE","LOVE");
This works because the methods are returning new String objects, so you can concatenate them.
Now when you use System.out.println(str); the result will be I LOVE JAVATHE MOST
(because you forgot the space when concatenating the two strings).
The line:
str.replace("LIKE","LOVE");
returns a String that holds the answer that you want, which you throw away. One easy fix is to change the last line:
System.out.println(str.concat("the most").toUpperCase().replace("LIKE","LOVE"));
and delete the useless calls above it.
String str = "I like Java"instead.