Getting Java Exception in thread "main" java.lang.error: unresolved compilation problem:

Question

Problem :

I am having a trouble while importing classes and setting variables and also I need help with my test program which I am doing. I want to test a program that simply outputs what the input was and puts the time stamp ( like Skype does ). I am having the trouble in getting a message and time variable type to work! Below is my code:

class MyTest {
    public static void main(String[] args) {

        Scanner myinput = new Scanner(System.in);
        Message mymessageObject = new Message ();
        Time mytimeObject = new Time ();

        System.out.println("Please enter your message here: ");
        String mymessage = myinput.nextLine();

        mymessageObject.simpleMessage(mymessage);
        mytimeObject.getTime();
    }

    void mysimpleMessage(String mymessage) {
        System.out.println(mymessage + mytime);
    }
}

And below is my error:

Exception in thread "main" java.lang.Error: Unresolved compilation problems: 
Message cannot be resolved to a type
Message cannot be resolved to a type
The constructor Time() is undefined
at MyTest.main(Test.java:8)

 

Answer 1

Your problem is in following line: Message mymessageObject = new Message ();
Above error says that your Message class is not known to compiler at compile time.

So you need to simply import a Message class.

Something like below code:

import package1.package2.Message;

You can simply refer the below link for further information.

http://docs.oracle.com/javase/tutorial/java/package/usepkgs.html

Answer 2

Your difficulty is in this line: Message messageObject = new Message ();
This error indicates that the Message class is not familiar at compile time.

So you require to import the Message class.

Something like this:

import package1.package2.Message;

I had a pair of various Java versions installed on my system. Hence foremost I uninstalled them all. Then I reinstalled the one i wanted to employ (which in my case is 8.0_151).

Then:

1. Go to Preferences >> Java >> Installed JRE's

2. Click on  add and browse to \Program Files\Java\jdk1.8.0_151

   In my example the "Location" variable for the jre did not alter however the "Name" variable for the jre in this dialog box did.  I am not certain the influence of this however it is the only matter that seems to have altered.  Who knows, maybe "refreshing" this variable is the key.

3. Click OK and then place the newly included jre as the default.  

4. Click OK, tell a small prayer and run a job.

Hopefully, You are able to solve this problem.