BlueJ String Conditional Error

Question

My BlueJ is running the wrong lines in the conditional statement if. My program is:

import java.io.*;
public class version_check
{
    public static void main(String args[])throws IOException
    {
        BufferedReader read=new BufferedReader(new InputStreamReader(System.in));
        System.out.println("Enter your BlueJ version");
        String version=read.readLine();
        if(version!="3.1.1")
        System.out.println("You need to upgrade your BlueJ version");
        else
        System.out.println("You have the latest BlueJ version");
    }
}

Output screen:

Enter your BlueJ version
3.1.1
You need to upgrade your BlueJ version

What mistake am I making?

Read [How do I compare strings in Java?](http://stackoverflow.com/questions/513832/how-do-i-compare-strings-in-java) — PakkuDon, Mar 22 '14 at 03:32
I want to know the sign for is not equal to(I was knowing the link you told in your last comment). — Rachit Bhargava, Mar 22 '14 at 03:36

score 1 · Answer 1 · answered Mar 22 '14 at 04:05

1

Use .equals to compare strings.

if(version!="3.1.1")   
        System.out.println("You need to upgrade your BlueJ version");

to

if(!(version.equals("3.1.1")))   
        System.out.println("You need to upgrade your BlueJ version");

answered Mar 22 '14 at 04:05

Oscar F

323
2
9
21

score 0 · Answer 2 · answered Feb 10 '15 at 15:23

The only comparison methods i know of for String types are the: 1.>String_variable.equals(String_to_be_checked_with) and the 2.>String_variable.equalsIgnoresCase(String_to_be_checked_with)

the second ignores the case of the string value that has been entered...

the easiest solution to your problem is:

if(version.equals("3.1.1"))
{
    System.out.println("You have the latest BlueJ version");        

}
else {
    System.out.println("You need to upgrade your BlueJ version");
}

Please check other answers first before you write one. This was already answered. — Jan Doggen, Feb 10 '15 at 16:21

score 0 · Answer 3 · edited Nov 08 '20 at 12:07

0

     import java.io.*;
     public class version_check
      {
        public static void main(String args[])throws IOException
         {
          BufferedReader read=new BufferedReader(new 
     InputStreamReader(System.in));
       System.out.println("Enter your BlueJ version");
        String version=read.readLine();
       if(!version.equals ("3.1.1"))
          System.out.println("You need to upgrade your BlueJ 
       version");
    else
         System.out.println ("You have the latest BlueJ version");
            }
           }

edited Nov 08 '20 at 12:07

tgdavies

10,307
4
35
40

answered Nov 07 '19 at 11:01

shreyash mali

1
3

While this code snippet may solve the question, [including an explanation](http://meta.stackexchange.com/questions/114762/explaining-entirely-code-based-answers) really helps to improve the quality of your post. Remember that you are answering the question for readers in the future, and those people might not know the reasons for your code suggestion. – Prince Vegeta Nov 07 '19 at 11:23

BlueJ String Conditional Error

3 Answers3