Difference between Sourcepath, Classpath and Buildpath

Terms like Sourcepath, Classpath, and Buildpath are frequently used in software development. Understanding these terms is essential during developing and compiling an application, specially in IDEs. Let us understand the differences between these paths.

1. Sourcepath

In Java, the term “Sourcepath” refers to the root path or directory where the Java compiler (javac) searches for the source code files (.java files) to compile into bytecode (.class files).

By default, the compiler searches the Java files relative to the current working directory. When we compile a Java program, we can provide the sourcepath to the compiler. In the following example, the Java compiler will search the HelloWorld.java in the directory /path/to/source.

javac -sourcepath /path/to/source HelloWorld.java

Build tools such as Apache Maven and Gradle, as well as integrated development environments (IDEs) like Eclipse, NetBeans and IntelliJ IDEA provide mechanisms to configure the sourcepath within the project settings. These tools manage the compilation process and automatically handle the sourcepath for us.

The following example demonstrates how IntelliJ idea configures the source folder for a Maven project:

2. Classpath

The classpath specifies the locations in which the JRE/JVM should search for classes and resources during compile time and runtime. The runtime resources are generally the compiled bytecode (*.class files), standard JDK libraries and other libraries (JAR files) imported into the project to run the Java program.

During compilation, we can pass the classpath as a command-line argument as follows:

java -classpath .;C:\dependency\framework.jar HelloWorld.java

Or we can set classpath in the environment variables of the machine to reuse it everytime a Java program is executed in the machine.

We can learn more about classpath in this article.

3. Buildpath

The buildpath is a general term that includes all the necessary locations to find the resources, including sourcepath and classpath as well. It specifies where the compiler and runtime environment should look for external libraries, JAR files, and other resources needed by the application.

The term buildpath is used mainly when we are talking about Java development tools such as IDEs or Maven/Gradle. The IDE or build tool uses the buildpath to compile the source files, generate bytecode, and package the project into a distributable form (such as a JAR or WAR file).

4. Summary

In order to fully understand the differences between sourcepath, classpath and buildpath we should follow the general idea of Java application development.

Firstly, during the development process, Java classes are compiled into class files and this process introduces the term “Sourcepath”. The sourcepath defines the locations of the source code files (.java files), that are required for the compilation of the project during the development stage.

Once these source code files are converted into class files we encounter the term classpath. The classpath specifies the locations where the JVM can find compiled classes(.class files) and libraries during the compilation and runtime.

Lastly, IDEs use the buildpath to define the configurations and locations where the compiler can find the necessary source code files and libraries during the build process.

Happy Learning !!