Enable -Xlint for VSCode Java Compiling

The Java extensions for VSCode do an excellent job of catching most warnings, but recently I came across several warnings in my project that VSCode was not reporting but which I found through compiling using the -Xlint flag.

Take this SSCCE for example:

public class Test
{
    public static void main(String[] args)
    {
        int x = 3;
        int y = (int)x;

        System.out.println(y);
    }
}

This code runs perfectly fine with no warnings in VSCode, but if you compile it with javac -Xlint Test.java, you will get this:

Test.java:6: warning: [cast] redundant cast to int
        int y = (int)x;
                ^      
1 warning

What I would like is a way of having these warnings get reported in VSCode just like other warnings (where they are highlighted with yellow squiggles that you can mouse over). I have tried, unsuccessfully, to see if there was a way of changing the default javac compiler arguments but have not found the configuration option (if it exists).

And the above warning is just a single example of things VSCode does not appear to report. I have found other warnings through using the -Xlint flag as well, such as fields that should be marked transient that are not.

Edit: I have opened a feature request for RedHat's VSCode Java extension here.

SonarLint may be what you need.

> SonarLint is an easy-to-use extension that helps you find and fix bugs and security issues as you code. The extension runs in the background and, just like a spell checker, highlights source code issues that pose a quality or security concern. The extension not only tells you what the issue is but also provides in-context guidance on why it's harmful and how to fix it, with examples. The extension supports over 500+ Java rules and includes several Quick Fixes to automatically fix certain quality issues

• https://code.visualstudio.com/docs/java/java-linting#_sonarlint

Install the Code Runner extension, and then you have two ways to modify the command

1. Search code-runner.executorMap on the Seting panel, click Edit in settings.json

   

2. Modify in the opening settings.json

   		"java": "cd $dir && javac $fileName && java $fileNameWithoutExt",
   

   for

   	    "java": "cd $dir && javac -Xlint $fileName && java $fileNameWithoutExt",
   

   

3. Right -click Run Code (Ctrl+Alt+N), or the upper right triangle button select Run Code

   

1. Add the following configuration to settings.json

   	"code-runner.customCommand": "cd $dir && javac -Xlint $fileName && java $fileNameWithoutExt",
   

2. Use the following method to execute the script

   <kbd>Ctrl</kbd>+<kbd>Shift</kbd>+<kbd>P</kbd> --> Run Custom Command (Ctrl+Alt+K)

   

You can add the following settings to make Code Runner output in the TERMINAL instead of the OUTPUT panel

	"code-runner.runInTerminal": true,

Under normal circumstances, we still recommend that you use the Extension Pack for Java to obtain more functions and better experiences.