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Java9/Examples
This is an informal page listing out examples of features that are implemented for Java 9. You are welcome to try out these examples. If bugs are found please check [here] for duplicates first and if not found, please file a bug.
Sub Feature | Feature Title / Try It Out Steps | Expected Result |
---|---|---|
The Pre-requisite: Java 9 JRE Support | ||
Add Java 9 JRE | Use Eclipse Preferences -> Java -> Installed JREs -> Add | Java 9 JRE recognized as a valid JRE |
Project JRE | In Package Explorer Use Project Context Menu and add Java 9 JRE | JRE specific (eg Object) gets resolved in the project. |
Package Explorer | Go to Package Explorer and expand the Java 9 JRE | Modules (eg java.base etc) are listed in the package explorer view |
The First Step: Module Creation | ||
Manual | Context Menu of src -> New -> File - give the module-info.java as name | no compiler errors |
Automatic | Context Menu of Project -> Cofigure -> Create module-info. | A default module-info.java with all packages exported should be created |
Basic Necessity : Compilation, Module Dependency & Error Reporting | ||
Unspecified Dependency | create projects "first" and "second" and create module-info.java files in each of giving the module names "first" and "second" respectively. In the first module add statement requires second; | Compiler gives error "second cannot be resolved to a module" |
Define Dependency | In the above scenario, add Project second as a dependent project for project first | Compiler error goes away |
Duplicate Dependency | Continuing from the above scenario, add a duplicate requires second; statement in the module-info.java file of the first | Compiler gives error "Duplicate requires entry: second" |
Circular Dependency | add a circular dependency ie add second project dependent on first and then add requires first; statement in the module-info.java file of the second | Two compiler errors " Cycle exists in module dependencies, Module second requires itself via first" |
Editing with Ease: Completion in module-info.java file | ||
Keyword Completion | In a module-info.java file, after module module_name {, press completion key (for eg, ctrl+space in windows) | keywords exports, opens, requires, provides and uses shown |
Keyword Completion - 2 | after exports packagename, or opens packagename press completion key | keyword to is shown as an option |
Package Completion | after exports, opens, provides or uses, press completion key | package completion shown. |
Type Reference Completion | after exports, opens, provides or uses, or optionally after a dot after a package, ie exports packagename. press completion key | Type completion shown. |
Implementation TypeRef Completion | after provides Typename with press completion key | Type completion shown and these typereferences are implmentations of the type given before with. |
The Essential Utilities: Code Select, Hover, Navigate, Search and Rename | ||
Module Select & Hover | In the module-info.java file of the first project, select second in the requires second; statement | Hover appears |
Module Select, Hover & Navigate | In the above scenario, after hover appears, click on the navigate | module-info.java file of second opened |
Module Select, & Search | In the module-info.java file of the second project, select second in the module second; statement and search for references | In the search view, the reference of second in directive requires second in file first -> module-info.java is shown. |
Package Search | create package pack1 to the project first, add exports pack1 in module-info.java file of first, and search for references of pack1 | In the search view, the reference of pack1 in directive exports pack1 in file first -> module-info.java is shown, similar to other pack1 references if any |
Type Search | create Type X in the project first, add uses X; in module-info.java file of first, and search for references of X | In the search view, the reference of X in directive uses X in file first -> module-info.java is shown, similar to other X references if any |
Code Select & Rename | in module-info.java file of first, select X in uses X; and rename to X11 | rename exhibits usual behavior - renames definition and references of X to X11 |