[java] Error: class X is public should be declared in a file named X.java

I am trying to write a program, but I'm getting this compiler error:

Main.java:1: error: class WeatherArray is public, should be declared in a file named WeatherArray.java
public class WeatherArray {
       ^
1 error

I have checked my file names, and my public class is the same as my .java file.

How can I fix this?

Here is my code:

public class WeatherArray {
    public static void main(String[] args) {
        // ...
    }
}

I my case, I was using syncthing. It created a duplicate that I was not aware of and my compilation was failing.

when you named your file WeatherArray.java,maybe you have another file on hard disk ,so you can rename WeatherArray.java as ReWeatherArray.java, then rename ReWeatherArray.java as WeatherArray.java. it will be ok.

You named your file as Main.java. name your file as WeatherArray.java and compile.

From Ubuntu command line:

//WeatherArray.java
public class WeatherArray {
  public static void main(String[] args) {
    System.out.println("....Hello World");
}}

ls

WeatherArray.java

javac WeatherArray.java

ls

WeatherArray.java WeatherArray.class

java WeatherArray

....Hello World

Of course if you name your java file with different name than WeatherArray, you need to take out public and it would be:

// Sunny.java
class WeatherArray {
   public static void main(String[] args) {
      System.out.println("....Hello World"); }}
// javac Sunny.java; java WeatherArray

I had the same problem but solved it when I realized that I didn't compile it with the correct casing. You may have been doing

javac Weatherarray.java

when it should have been

javac WeatherArray.java

In my case (using IntelliJ) I copy and pasted and renamed the workspace, and I am still using the old path to compile the new project.

In this case this particular error will happen too, if you have the same error you can check if you have done the similar things.

The name of the public class within a file has to be the same as the name of that file.

So if your file declares class WeatherArray, it needs to be named WeatherArray.java

your file is named Main.java where it should be

WeatherArray.java

To avoid this error you should follow the following steps:

1) You should make a new java class

2) Name that class

3) And a new java class is made

I encountered the same error once. It was really funny. I had created a backup of the .java file with different filename but the same class name. And kept on trying to build it till I checked all the files in my folder.

This happens when you have 1 name for the Java class on hard disk and another name of Java class in the code!!

For example, I renamed my MainActivity class to MainnActivity only (!) in the code. I got this error immediately.

There is also a visual indicator in the Project tab of Android Studio - a class inside a class, like you have nested classed, but with an error indicator.

The solution is to simply rename class name in the Project tab (SHIFT + F6) to match the name in the Java code.

The answer is quite simple. It lies in your admin rights. before compiling your java code you need to open the command prompt with run as administrator. then compile your code. no need to change anything in your code. the name of the class need to be the same as the name of the java file.. that's it!!

error example:

public class MaainActivity extends Activity {

  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    // Get the view from activity_main.xml
    setContentView(R.layout.activity_main);

  }
}

correct example:just make sure that you written correct name of activity that is"main activity"

public class MainActivity extends Activity {


  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    // Get the view from activity_main.xml
    setContentView(R.layout.activity_main);

  }
}

The terminal is not case sensitive when writing "Javac [x].java", so make sure what you write in the terminal matches the filename and class name.

My class name and file name were both "MainClass", but I was compiling using "Mainclass". Notice I forgot to make the "c" capital.