Interoperability: Invoking Java Functions from C
Despite the inherent differences between C and Java, the ability to call Java functions from C can be crucial in various scenarios. This article will explore the methodology behind this integration, excluding methods that involve external commands like CMD.
JVM Creation and Method Invocation
To interact with Java code, a Java Virtual Machine (JVM) must be created within the C application. As illustrated in "Creating a JVM from C," the procedure involves initializing a Java Virtual Machine, loading the desired Java class, and invoking its methods.
JNI and Pointer Caching
The Java Native Interface (JNI) serves as the bridge between Java and C . It provides a set of native methods that enable C programs to access Java classes, objects, and methods. JNIEnv* is a pointer that represents the JNI environment and allows for direct interaction with the JVM.
Caching Considerations
When caching JNIEnv pointers, one must exercise caution. The semantics of JNI pointer caching can be complex. The JNI reference documentation outlines the specific guidelines for acceptable caching practices. By adhering to these guidelines, C programs can effectively cache JNIEnv pointers and interact with the Java runtime as needed.
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