v8.registerJavaMethod((receiver, parameters) -> String name = parameters.getString(0); return "Hello, " + name + " from Java!"; , "greet"); v8.executeVoidScript("var message = greet('Developer'); console.log(message);"); Let’s look at realistic performance metrics. A benchmark testing recursion, Fibonacci calculation, and JSON parsing:
<dependency> <groupId>com.eclipsesource.j2v8</groupId> <artifactId>j2v8</artifactId> <version>6.2.0</version> <!-- Check for latest repack version --> <classifier>linuxx86_64</classifier> <!-- Choose your OS: win32x86, macosx64, android_arm --> </dependency> Note: The classifier ensures you download the pre-repacked native library for your OS. Here is a simple Java program that executes JavaScript inside the V8 engine: java addon v8 repack
Introduction In the modern software development landscape, the lines between different programming languages are blurring. Java, a stalwart of enterprise backends, is no longer confined to its own ecosystem. Developers are increasingly looking for ways to integrate the speed and flexibility of JavaScript directly into their Java applications. Java, a stalwart of enterprise backends, is no
Create one V8 runtime per thread, or use a pool of runtimes. Pitfall 3: Native Library Loading If the repacked native library (e.g., libj2v8_linux_x86_64.so ) is not in your java.library.path , you will get UnsatisfiedLinkError . Pitfall 3: Native Library Loading If the repacked
try // Execute simple JavaScript int result = v8.executeIntegerScript("const a = 5; const b = 10; a + b;"); System.out.println("JS Result: " + result); // Output: 15 // Execute multi-line script with function v8.executeVoidScript("function multiply(x, y) return x * y; "); // Call the JS function from Java Object multiplyResult = v8.executeJSFunction("multiply", 7, 8); System.out.println("Multiplication result: " + multiplyResult); // Output: 56 finally // Crucial: Release native memory to avoid leaks v8.release();
| Engine | Time (ms) for 1M iterations | Memory Overhead | |-----------------------|------------------------------|------------------| | Java (native) | 12 ms | N/A | | | 45 ms | 28 MB | | Nashorn (Java 8) | 210 ms | 95 MB | | Rhino (interpreted) | 1,800 ms | 210 MB |