JDB

Simple API for JDB (Java debugger).

---

❇ Introduction

The Java Debugger (JDB) is a simple command-line debugger. The objective of this project is to facilitate the use of this debugger without having to worry about creating a process, redirecting output, among others.

❓ How to use

1. Add one of the options below to the pom.xml file:

Using Maven Central (recomended):

<dependency>
  <groupId>io.github.wniemiec-component-java</groupId>
  <artifactId>jdb</artifactId>
  <version>LATEST</version>
</dependency>

Using GitHub Packages:

<dependency>
  <groupId>wniemiec.component.java</groupId>
  <artifactId>jdb</artifactId>
  <version>LATEST</version>
</dependency>

2. Run

$ mvn install

3. Use it

[...]

import wniemiec.component.java.JDB;

[...]

Path workingDirectory = Path.of(".", "bin").toAbsolutePath().normalize();
Path sourcePath = workingDirectory
		.resolve(Path.of("..", "tests"))
		.normalize();
List<Path> classpaths = List.of(workingDirectory);
List<Path> sourcePaths = List.of(
		workingDirectory.relativize(sourcePath)
);
		
JDB jdb = new JDB.Builder()
		.workingDirectory(workingDirectory)
		.classPath(classpaths)
		.srcPath(sourcePaths)
		.build();
jdb.run().send("stop at api.jdb.testfiles.Calculator : 8")

String line = jdb.read();

// Runs until it reaches the breakpoint on line 8
while (!line.contains("Breakpoint")) {
	line = jdb.read();
	System.out.println(line);
}

jdb.send("step into");	// Enters the function

line = jdb.read();
System.out.println(line);

[...]

📖 Documentation

Property	Parameter type	Return type	Description	Default parameter value
run	void	JDB	Initializes JDB in a new process	-
quit	void	void	Stops JDB process	-
forceQuit	void	void	Try to stops JDB process immediately	-
send	command: String	JDB	Sends a command to JDB. After calling this method, it is necessary to call read() for JDB to process the command	-
send	commands: String...	void	Sends a command to JDB. After calling this method, it is necessary to call read() for JDB to process the command	-
read	void	String	Reads JDB output. This method will block until some input is available, an I/O error occurs, or the end of the stream is reached	-
readAll	void	List<String>	Reads all available JDB output. This method will not block if no output is available	``
isReady	void	boolean	Checks if there is an output available	-
waitFor	void	void	Causes the current thread to block until JDB is finished	-
isRunning	void	boolean	Checks whether JDB is running	-

🎮 Commands

Here are the main commands that can be sent to the debugger using the send method.

Command	Description
stop at <class_name>:<line_number>	Sets up a breakpoint at a particular line number
stop in <class_name>:<method_name_or_variable_name>	Sets up a breakpoint on a particular method or on a particular variable
clear	Removes all breakpoints
exit	Closes JDB
run	The execution stops at the first line of the main method.
step into	Step to the next line of the code. If the next line of the code is a function call, then it enters the function by driving the control at the top line of the function.
step over	Step to the next line of the code. If the next line is a function call, it executes that function in the background and returns the result.
cont	Continues execution of the debugged application after a breakpoint, exception, or step. It will stop only if it passes through a breakpoint.

🚩 Changelog

Details about each version are documented in the releases section.

🤝 Contribute!

See the documentation on how you can contribute to the project here.

📁 Files

/

Name	Type	Description
dist	Directory	Released versions
docs	Directory	Documentation files
src	Directory	Source files

See more

• Oracle - jdb - The Java Debugger
• Tutorials point - JDB quick guide