I can't run the code that I make on eclipse on other IDEs or VSCode-CodePudding

i'm studying java(i'm a beginner) in college and we use eclipse. i would like to try other ides but i can't run code on any other than eclipse. we do not use a main class, i know that may sound weird, but it works in eclipse (i guess). we do exercises with arrays matrixes images, colours that kinda stuff. here's an example:

static boolean[][] chessMatrix(int lines) {
    boolean[][] m = new boolean[lines][lines];
    for (int i = 0; i < m.length; i  ) {
        for (int j = 0; j < m.length; j  ) {
            if ((i   j) % 2 == 0) {
                m[i][j] = true;
          } else
                m[i][j] = false;
       }
    }
return m;
}

this code runs perfectly fine on eclipse, we use a debugger made by some college professors on intelij, for example, it does not even give me the option to run. i have tried importing the src file directly, changed jre/sdk versions and i can't get it to work. any help is appreciated, thanks!

CodePudding user response：

Method needs to be part of a class, easiest is to create a class with a main method and put your method inside that class.

Example:

public class Main {

    public static void main(String[] args) {
        chessMatrix(10);

    }

    static boolean[][] chessMatrix(int lines) {
        boolean[][] m = new boolean[lines][lines];
        for (int i = 0; i < m.length; i  ) {
            for (int j = 0; j < m.length; j  ) {
                if ((i   j) % 2 == 0) {
                    m[i][j] = true;
                } else
                    m[i][j] = false;
            }
        }
        return m;
    }
}

Given the source above being saved as file "Main.java", you can compile first, then run that using:

javac -d . Main.java
java Main

Never versions of Java (AFAIK 11 and above) can also compile and run source code directly, using

java Main.java

Notes:

the method above just created and returns a sqare array of boolean, so expect no visible output
things get complicated when you use multiple source files, packages and external libraries. That's the time you should consider using build management tools like Apache Maven or Gradle.

CodePudding user response：

You need to write your code inside a class:

public class MyClass {

}

You can call your method in the main method. This method gets executed, when you press run.

Your code should look like this:

public class MyClass {

   public static void main(String args[]) {
      System.out.println(chessMatrix(10));
    }

   static boolean[][] chessMatrix(int lines) {
       boolean[][] m = new boolean[lines][lines];
       for (int i = 0; i < m.length; i  ) {
          for (int j = 0; j < m.length; j  ) {
              if ((i   j) % 2 == 0) {
                  m[i][j] = true;
            } else
                  m[i][j] = false;
         }
      }
      return m;
    }
}