Java Build Path
The options in this page indicate the build path settings for a Java project. You can reach this page through the project properties (Project > Properties > Java Build Path) from the context menu on a created project or the
File menu of the workbench.
The build class path is a list of paths visible to the compiler when building the project.
Source tab
Source folders are top-level folders in the project hierarchy. They are the root of packages containing .java files.
The compiler will translate the contained files to .class files that will be written to the output folder.
Source folders allow to structure the project, for example to separate
test from the application in two source folders. Within a source folder, a more detailed structuring can be acived by using packages.
Each source folder can define an exclusion filter to specify which
resources inside the folder should not be visible to the compiler.
Resources existing in source folders are copied to the output folder unless the setting in the
Java > Compiler > Building preference
page specifies that the resource is filtered. The output folder is defined per project except if a source folder specifies its own output folder.
Source folder options:
Option |
Description |
Add Folder |
Creates a new folder to contain source |
Link Source |
Creates a new folder that links to an location outside of the workspace |
Edit |
Allows to modify the currently selected
source folder or source folder attribute. |
Remove |
Removes the selected folders from the class path. This does not
delete the folders nor their contents. |
Allow output folder per source folder |
Shows/Hides the 'output folder' attribute of the source folders |
Source folder attributes:
Attribute |
Description |
Exclusion filter |
Selects which resources are not visible to the compiler |
Output folder |
Only available when Allow output
folder per source folder is checked. Defines a source folder specific output location. If not set the project's default output folder is used. |
Native library location |
Defines the folder that contains the native libararies
(for example 'dll' or 'o' files) required at runtime by the sources in the source folder.
|
At the bottom of this page, the Default output folder field allows you to enter a path to a folder path where the compilation output for this
project will reside. The default output is used for source folders that do not specify an own output folder. Use Browse to select an existing location from the current project.
Projects tab
In the Required projects on the build path list, you can add project dependencies by selecting other workbench
projects to add to the build path for this new project.
Adding a required project indirectly adds all its classpath entries marked as 'exported'. Setting a classpath entry as exported is done in the Order and Export tab.
The projects selected here are automatically added to the referenced projects list. The referenced project list is used to determine the build order. A project is always
build after all its referenced projects are built.
Action |
Description |
Add |
Add another project in the workspace to the build path of this project. |
Edit |
Edit the classpath attribute of a required project. |
Remove |
Removes the selected required projects from the list. |
Project entry attributes:
Attribute |
Description |
Native library location |
Specifies where native library required for the project to operate can be found. |
Access rules |
Specifies access rules for project contained in the library. This allows to hide content of a project. |
Libraries tab
On this page, you can add libraries to the build path.
By default, the library list contains an entry representing the Java runtime library. This entry points to the JRE
selected as the default JRE. The default JRE is configured in the
Java > Debug > Installed JREs preferences page.
Libraries tab options:
Option |
Description |
Add JARs |
Allows you to navigate the workbench hierarchy and select JAR files to add to the build path. |
Add External JARs |
Allows you to navigate the file system (outside the workbench) and select JAR files to add to the build path. |
Add Variable |
Allows you to add classpath variables to the build path. Classpath variables are an indirection to JARs with the benefit of avoiding local
file system paths in a classpath. This is needed when projects are shared in a team.
Variables can be created and edited in the
Java > Build Path > Classpath Variables preference page. |
Add Library |
Allows to add a predefined libraries like the JRE System Library. Such libraries can stand for an arbitrary number of entries (visible as children node of the library node) |
Add Class Folder |
Allows to navigate the workbench hierarchy and select a class folder for the build path. The selection dialog also allows you to create a new folder. |
Add External Class Folder |
Allows to navigate the file system (outside the workbench) and select a class folder for the build path. The selection dialog also allows you to create a new folder. |
Edit |
Allows you to modify the currently selected library entry or entry attribute |
Remove |
Removes the selected element from the build path. This does not delete the resource. |
Migrate JAR File |
Migrate a JAR on the build path to a newer version. If the newer version contains refactoring scripts
the refactoring stored in the script will be executed. |
Libraries have the following attributes (presented as library entry children nodes):
Library entry attributes:
Attribute |
Description |
Javadoc location |
Specifies where the library's Javadoc documentation can be found. If specified you can use Shift+F2 on an element of this library to open its documentation. |
Source attachment |
Specifies where the library's source can be found. |
Native library location |
Specifies where native library required for the library to operate can be found. |
Access rules |
Specifies access rules for resources contained in the library. This allows to hide content of a library. |
Order and Export tab
In the Build class path order list, you can click the Up and Down buttons to move the selected path entry up or down in the build path order for this new project.
Checked list entries are marked as exported. Exported entries are visible to projects that require the project. Use the Select
All and Deselect All to change the checked state of all entries. Source folders are always exported,
and can not be deselected.
Build classpath
Classpath variables
Frequently asked questions on JDT
Classpath variables preferences
Build path preferences
Compiler preferences