JavaCC Source and Class Locations

JavaCC Source and Class Locations | Generated by AI

Home 2025.10

JavaCC Overview

JavaCC (Java Compiler Compiler) is a tool that generates Java source code (e.g., parser classes) from grammar specification files (.jj files). It does not directly compile code into bytecode (.class files)—that’s handled by a standard Java compiler like javac. If you’re using JavaCC programmatically (e.g., in an IDE or runtime environment) to generate and compile dynamic code, the output locations depend on how you configure it. I’ll break this down step by step, based on standard JavaCC behavior and common usage patterns.

Where JavaCC Generates Source Files

Default Output Location: JavaCC outputs generated .java files to the current working directory (or a subdirectory called “output” if not specified). You can override this with command-line options like -OUTPUT_DIRECTORY=<path> or programmatically via the JavaCCOptions class if invoking it in code.
Example Command-Line Usage:
```
javacc -OUTPUT_DIRECTORY=/path/to/generated MyGrammar.jj
```
This would create .java files (e.g., Token\ 0, Parser, ParseException) in /path/to/generated.
Programmatic Usage: If you’re calling JavaCC from within your Java application (e.g., using org.javacc.JavaCC.main() or similar APIs), you can set options to specify the output path. The source files are just plain .java files that need further compilation.

This aligns with official JavaCC documentation (e.g., from the legacy JavaCC project on SourceForge or Maven-based distributions), which states that generated classes are output to the specified directory as source code, not bytecode.

Where Compiled Classes Are Stored If You Compile the Generated Code

JavaCC itself doesn’t compile to .class files—you must do this manually or automate it in your code. Here’s what happens next:

Manual Compilation: Use javac on the generated .java files:
```
javac -d /path/to/classes MyGeneratedParser.java
```
- The -d flag specifies the output directory for .class files, often a classes/ folder or your project’s build target (e.g., target/classes/ in Maven/Gradle).
- Common locations: bin/, build/classes/, or target/classes/ depending on your build system (e.g., Ant, Maven).
Dynamic Compilation in Code: If you’re using JavaCC at runtime to generate parsers for dynamic code (e.g., for script interpretation or on-the-fly parsing), you’d typically:
1. Generate the .java files programmatically (e.g., writing to a temp directory like System.getProperty("java.io.tmpdir")).
2. Compile them using the Java Compiler API (javax.tools.JavaCompiler) or a library like Janino.
  - Example: Set the compilation output to a custom directory, such as new File("generated/classes").
  - The compiled .class files are stored in that directory. At runtime, use a custom ClassLoader to load them from there or in-memory buffers. - JVM Default: Without custom paths, classes might go to the default target/classes if using build tools, or to any directory you specify in the compilation task.
Common Dynamic Scenarios:
- In-Memory Compilation: Libraries like the Compiler API allow compiling without writing to disk, storing bytecode in memory via ClassLoader.defineClass(). No physical storage occurs.
- Temporary Storage: If the generated code is compiled and persisted, it often goes to /tmp/ on Unix-like systems or temporary folders. For production apps, use a dedicated generated/ or cache/ directory in your project’s file system.
- Frameworks: Tools like ANTLR (alternative to JavaCC) or custom runners might automate this, storing classes in RAM or a classpath folder (e.g., CLASSPATH entries).

Key Considerations and Best Practices

Runtime Safety: Dynamically compiling code carries risks (e.g., security issues). Ensure user-generated grammars are sandboxed.
Build Tools Integration: If using Maven or Gradle, JavaCC plugins (e.g., javacc-maven-plugin) output to target/generated-sources/javacc/ for sources and target/classes/ for compiled classes, configurable in your pom.xml or build.gradle.
Debugging: If compilation fails, check JavaCC’s error output or logs. Generated files are typically stored where your app runs, not globally.
Evidence from Docs: Per JavaCC’s official guide (javacc.github.io or legacy docs), output is directory-based and post-compilation handling is user-managed. Real-world examples in GitHub repos (e.g., search for JavaCC usage) show custom output dirs like src/main/generated/.

If this doesn’t match your setup (e.g., a specific framework or IDE), provide more details like your code snippet or environment, and I can refine the answer!

Back

x-ai/grok-4-fast:free

Donate