Handle Absolute JAR Path (#106)

* Handle absolute paths to JAR file

This commit fixes instances where the `jar` parameter is an absolute
path to the JAR file. Previously, the path for

```js
const java = new JavaCaller({
    jar: "F:\\my-path\\file.jar",
});
```

would become `./F:\\my-path\\file.jar`. Now, it is kept as-is, allowing
absolute paths to be provided.

* Handle absolute paths to JAR file

This commit fixes instances where the `jar` parameter is an absolute
path to the JAR file. Previously, the path for

```js
const java = new JavaCaller({
    jar: "F:\\my-path\\file.jar",
});
```

would become `./F:\\my-path\\file.jar`. Now, it is kept as-is, allowing
absolute paths to be provided.

* Fix handling of absolute paths

This commit fixes the handling of absolute paths, switching from
`path.join()` to `path.isAbsolute()` to handle differing behavior for
different platforms.

`path.join()` works differently for Windows paths and Linux paths.
`path.join(".", "C:\\") === "C:\\"`
`path.join(".", "/home/test") === "home/test"`

The latter is missing a leading `/` and thus is no longer an
absolute path.

As described in [this issue](GHSA-37v4-cwgp-x353),
there was a NodeJS [security vulnerability](https://nodejs.org/en/blog/vulnerability/january-2025-security-releases)
that caused the behavior of `path.join()` to be changed. Newer versions
of Node will return a relative path in these instances, so
`path.join(".", "C:\\") === ".\\C:\\"`.

---------

Co-authored-by: Nicolas Vuillamy <nicolas.vuillamy@gmail.com>

Author: BrendanC23

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## Unreleased
 
+- Fix to allow absolute path to JAR file
+
 ## [4.2.0] 2025-02-23
 
 - Upgrade to njre v1.4.2

lib/java-caller.js

@@ -207,10 +207,12 @@ class JavaCaller {
         let allArgs = [];
         allArgs.push(...javaArgs);
         if (this.jar) {
+            const jarPath = path.isAbsolute(this.jar) ? this.jar : path.join(this.rootPath, this.jar);
+            
             allArgs.push(
                 ...[
                     "-jar",
-                    os.platform() === "win32" && windowsVerbatimArguments ? `"${this.rootPath}/${this.jar}"` : `${this.rootPath}/${this.jar}`,
+                    os.platform() === "win32" && windowsVerbatimArguments ? `"${jarPath}"` : `${jarPath}`,
                 ],
             );
         } else {

test/java-caller.test.js

@@ -3,6 +3,7 @@
 const { JavaCaller } = require('../lib/index');
 const os = require("os");
 const which = require("which");
+const path = require('path');
 
 const {
     beforeEachTestCase,
@@ -175,4 +176,15 @@ describe("Call with classes", () => {
         await javaCli.process();
     });
 
+    it("Should work with an absolute path", async () => {
+        const absolutePath = path.join(process.cwd(), "test/java/jar/JavaCallerTesterRunnable.jar");
+
+        const java = new JavaCaller({
+            jar: absolutePath,
+        });
+        const { status, stdout, stderr } = await java.run();
+
+        checkStatus(0, status, stdout, stderr);
+        checkStdOutIncludes(`JavaCallerTester is called !`, stdout, stderr);
+    });
 });