java: unclosed string literal [Error]

If you try to run Java code in IntelliJ IDEA, the IDE for Java Programming, you may get "java: unclosed string literal" error if having an incorrectly defined String. A String Class object in Java must be enclosed in double quotes, if you miss them you will get this error.

package com.java.code2care.example;

public class Main {

    public static void main(String[] args) {

        System.out.println("Hello World!);

    }
}

/Main.java:9:28
java: unclosed string literal

As you can see the String Hello World! is missing a closing double quote, if you add it the error will be resolved. If you hover over the String in IntelliJ you will see the error - Illegal line end in string literal