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Eclipse Java Development User Guide
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What's New in 3.5 (JDT)

Here are descriptions of some of the more interesting or significant changes made to the Java development tools for the 3.5 release of Eclipse. They are grouped into:

See also the Eclipse Platform What's New in 3.5 document for changes in the Platform.


Java Editor
Constructor completion Content Assist can now propose the available constructors of a class when the completion happens in an allocation expression:

Constructor completion

If the class is not already imported (as shown in the example above), then the corresponding import will also be added.

Open Implementation hyperlink An Open Implementation hyperlink has been added for overridable methods, which directly opens the implementation in case there's only one, or shows all the concrete implementations for that method in the hierarchy of its declaring type, using the quick type hierarchy. By default, the hyperlink appears when you hold down the Ctrl key while hovering over an overridable method.

Open Implementation hyperlink for methods

You can configure the modifier for this hyperlink on the Opens the hyperlinking preference page General > Editors > Text Editors > Hyperlinking preference page.

Select comment with double click Double clicking on the beginning or end marker of a comment now selects the whole comment.
Quick Fix to start Rename refactoring The Rename refactoring can now also be started via Quick Fix (Ctrl+1):

Quick Fix 'Rename in workspace' in Java editor

Open in Properties File action in NLS Hover The NLS string hover now has an Open in Properties File action in the toolbar which locates the selected NLS string in the corresponding properties file where it is defined. The action is activated in the toolbar with focus on the hover.

Open in Properties File action in NLS hover

Formatter option to preserve user line breaks The Java code formatter can now optionally preserve user line breaks by not joining lines in code or comments.

For example, the wrapped lines of the return statement in following test case:

Example of Code to Format

will be preserved by the formatter when the Never join lines preference is used and now produces the following result:

Coded Formatted with Never Join Lines

This preference can be configured on the Opens the formatter preference page Java > Code Style > Formatter preference page. See the Never join lines option on the Line Wrapping and Comments tab.

Java Compare Editor
General editing enhancements The Java Compare editor now supports new text editing features like move/copy/delete line and formatting.
Hyperlinking (Ctrl+Click) Hyperlinking
Content Assist (Ctrl+Space) Content Assist
Javadoc on hover Javadoc hovers
Quick Outline (Ctrl+O) Quick outline
Reconcile Java compare structure while typing The Java compare editor now updates its structure while you are typing inside the editor.

Dynamic structure comparison

Java Refactoring and Source Actions
Generate toString() The new toString() generator allows you to quickly generate a toString() method for your class. Source > Generate toString()... offers several options to configure the format of the resulting String and the style of the generated code in the toString() method body.

Generate toString() dialog

Optionally use blocks when generating hashCode() and equals() The Generate hashCode() and equals() wizard now allows you to choose whether blocks are used for if statements:

Generate hashCode() and equals() wizard

Java Compiler
Comparing identical values Comparing identical values is now detected by the compiler and reported as a warning by default:

Comparing Identical Values Warning Example

You can configure this setting in the Potential programming problems section on the Opens the Errors/Warnings preference page Java > Compiler > Errors/Warnings preference page, or by clicking the Configure Problem Severity button in the problem hover toolbar.

Missing synchronized modifier The compiler now issues a warning when a method overrides a synchronized method but the method itself is not synchronized.

Problem hover with quick fix for missing synchronized modifier

You can use the quick fix to add the synchronized modifier, and you can configure the problem severity on Opens the Errors/Warnings preference page Preferences > Java > Compiler > Errors/Warnings in the Potential programming problems section.
Suppress compiler problem for 'switch' case fall-through The compiler problem for expected fall-throughs in switch case statements can now be suppressed by preceding the following case statement with a comment that starts with $FALL-THROUGH$. This is especially interesting for code that can't use the J2SE-5.0-style @SuppressWarnings("fallthrough") annotation.

Problem hover with quick fixes for switch case fall-through

This problem is not reported by default. You can enable the 'switch' case fall-through warning on Opens the Errors/Warnings preference page Preferences > Java > Compiler > Errors/Warnings in the Potential programming problems section.
Missing hashCode() method The compiler can now detect whether a class overrides the equals() method without overriding the hashCode() method:

Problem hover with quick fix for missing hashCode method

You can either use the quick fix to override the hashCode() method or the quick fix to regenerate both methods.

This problem is not reported by default. You can enable it on Opens the Errors/Warnings preference page Preferences > Java > Compiler > Errors/Warnings in the Potential programming problems section.

Dead code The compiler can now issue a warning if dead code is detected.

For instance, if (false) foo(); is not reported as truly unreachable code by the Java Language Specification. When this diagnostic is enabled, the invocation of foo() is signaled as dead code:

Problem hover with quick fix for dead code

This problem is reported as a warning by default. You can configure the problem severity on Opens the Errors/Warnings preference page Preferences > Java > Compiler > Errors/Warnings in the Potential programming problems section

Note that dead code following an if (constant variable) statement, e.g. if (DEBUG), is not reported.

Classpath resolution honors the 'Class-Path' header of JAR manifest file The 'Class-Path' header of a JAR manifest is now honored in the Java model. JARs defined by 'Class-Path' are now automatically added to the build path.

For example, 'nested.jar' is a referenced library although it was not explicitly specified in the project build path but through the manifest of 'lib.jar':

Class-Path Clause Example

Build path supports ".." The path of a library, variable or container entry can now be anywhere relative to the project, e.g. if the library is on a sibling directory, its path can be specified using the ".." as follows:

Parent Relative Path Example

Build path resolution tolerates duplicate entries Duplicate entries in the build path are now tolerated if the redundant entry is found while resolving the build path and not at the raw level.

For example, two user libraries used in the project build path referring to the same JAR file are tolerated:

Classpath Duplicate Entries Example

However, an error is reported if the same JAR file is directly specified twice:

Classpath Invalid Duplicate Entries Example

Compiler compliance follows execution environment When you change the JRE on the build path of a Java project to an execution environment, Eclipse now automatically updates the compiler compliance settings on the Java Compiler properties page to use the settings defined by the execution environment.

Java Compiler properties page

Note that as of 3.5, an execution environment is the first choice when creating a new Java project or a launch configuration.

Java Views and Dialogs
Emphasized matching characters in Open Type dialog The Open Type dialog now emphasizes the characters that match the pattern:

Emphasized matching characters in Open Type dialog

Sort working sets in Package Explorer The Configure Working Sets... dialog now has a Sort working sets option to sort working sets alphabetically. The setting is preserved, so the working sets stay sorted, even as new working sets are added.

Sort working sets in Package Explorer

You can enable working sets in the Package Explorer via the Top Level Elements > Working Sets view menu.
Delete working sets from the Package Explorer The Delete functionality is now enabled for working sets when the top level elements are Working Sets in the Package Explorer. When deleting working sets, you can now either remove or just hide them from the Package Explorer:

Delete working sets from a Package Explorer

Paste patch into Package Explorer What's the quickest way to apply a patch from Bugzilla? Just open the attachment, copy the patch to the clipboard and paste it into the Package Explorer.
Call Hierarchy can expand with constructors In Callers mode, the Call Hierarchy now has an Expand With Constructors action in the context menu for instance methods.

This action replaces the normal children of the method with

  • the constructors of the method's declaring class
  • a node that contains the direct callers of the method.
This is useful for methods in anonymous classes, for example to follow the callers that create a Runnable, instead of those which actually call its run() method.

Expand With Constructors

Some methods (e.g. java.lang.Runnable#run()) are expanded with constructors by default. The defaults can be configured in the view menu.

Improved Javadoc view and hover The Javadoc view and hovers now support the {@inheritDoc} tag and add links to overridden methods (like the Javadoc tool):

Improved Javadoc hover

Moreover, the message for deprecated elements now shows up on top, and relative links are supported (for example, to embed images from the "doc-files" directory or to link to {@docRoot}).

Open *.jardesc files with JAR Export Wizard Opening *.jardesc files now launches the JAR Export Wizard by default.

Open With > JAR Export Wizard

The Open JAR Packager... action in the context menu is gone.

Open test result files in JUnit view JUnit test result files from Eclipse or the Ant JUnit tasks can now be opened in the JUnit view via double click or via Open With > JUnit View.

Open With > JUnit View

If the files are not inside your workspace, you can still open them from the JUnit view via the Test Run History... drop-down menu. And the Import... and Export... actions now always start at the most recently used location.

Test Run History... > Import

JUnit 4.5 The JUnit4 version shipped with Eclipse has been updated to 4.5. See their Release Notes for the changes in version 4.5.
Runnable Jar-in-Jar exporter can package libraries The Runnable JAR File Export wizard can now also package the required libraries into the exported runnable JAR file or into a folder next to the JAR:

Runnable JAR File Export wizard

The advantage of the second and third options is that the required libraries will just be copied and don't need be repackaged.


 
 
  Published under the terms of the Eclipse Public License Version 1.0 ("EPL") Design by Interspire