Merge pull request #6 from vadage/develop

Merge develop into main

Author: vadage

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "jvm-hook"
-version = "0.1.1"
+version = "0.2.0"
 edition = "2021"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

README.md

@@ -13,7 +13,7 @@ Keep this in mind as you use this feature in your projects.
 
 ## Compatibility
 ### ✅ Java
-All Java versions should be supported, as `jni` is only used for the structs and no method calls or such.<br>
+The export `JVM_DefineClassWithSource` was only added in JDK1.5, therefore all Java versions starting from `Java 6` are supported (there is no JNI version for `Java 5`).<br>
 Thus far only `Java 8`, `Java 20` and `Java 21` were explicitly tested.
 
 ### ✅ Operating system

src/class_loader.rs

@@ -1,4 +1,4 @@
-use std::mem;
+use std::ops::Deref;
 use std::os::raw::c_char;
 use std::slice::from_raw_parts_mut;
 
@@ -26,9 +26,8 @@ impl ClassLoader {
     pub unsafe fn setup_hook() {
         let handle = Library::new("jvm").expect("Could not find jvm library.");
         let method = handle.get::<DefineClassCommon>(b"JVM_DefineClassWithSource").expect("Could not find exported function.");
-        let target: DefineClassCommon = mem::transmute(method);
 
-        let hook = DefineClassCommonHook.initialize(target, ClassLoader::hooked_define_class_common).expect("Could not initialize hook for class loading.");
+        let hook = DefineClassCommonHook.initialize(*method.deref(), ClassLoader::hooked_define_class_common).expect("Could not initialize hook for class loading.");
         hook.enable().expect("Could not to hook into class loading.");
     }
 

src/lib.rs

@@ -3,11 +3,11 @@ mod jvm;
 
 use std::os::raw::c_void;
 use jni::JavaVM;
-use jni::sys::{jint, JNI_VERSION_1_1};
+use jni::sys::{jint, JNI_VERSION_1_6};
 use class_loader::ClassLoader;
 
 #[no_mangle]
 pub unsafe extern "system" fn JNI_OnLoad(_: JavaVM, _: *mut c_void) -> jint {
     ClassLoader::setup_hook();
-    return JNI_VERSION_1_1;
+    return JNI_VERSION_1_6;
 }