noteworthy/source/jdt.adoc - www.eclipse.org/oxygen - Git at Google

 [[jdt-java-development-tools]]
 == Java development tools

 [[jdt-java-java9]]
 === Java 9

 ==== Support for Building Java 9 Applications

 The Java™ 9 specification has not been released yet and so support has not yet been integrated into our standard download packages. You can add an early access preview to the Eclipse IDE, Oxygen Edition (4.7).

 The Eclipse Java™ 9 Support (BETA) contains the following:

 * ability to add JRE and JDK 9 as installed JRE;
 * support for JavaSE-9 execution environment;
 * ability to create Java and Plug-in projects that use a JRE or JDK 9; and
 * ability to compile modules that are part of a Java project

 [NOTE]
 ====
 This is an implementation of an early-draft specification developed under the Java Community Process (JCP) and is made available for testing and evaluation purposes only. The code is not compatible with any specification of the JCP.
 ====

 For up-to-date information, please see https://marketplace.eclipse.org/content/java-9-support-beta-oxygen[Java 9 Support (BETA) for Oxygen] in the Eclipse Marketplace.

 Install the beta by dragging the install button onto your running Eclipse IDE, Oxygen Edition instance.

 ++++
 <div style="text-align:center">
 <a href="http://marketplace.eclipse.org/marketplace-client-intro?mpc_install=2393593" class="drag" title="Drag to your running Eclipse* workspace. *Requires Eclipse Marketplace Client"><img class="img-responsive" src="https://marketplace.eclipse.org/sites/all/themes/solstice/public/images/marketplace/btn-install.png" alt="Drag to your running Eclipse* workspace. *Requires Eclipse Marketplace Client" /></a>
 </div>
 ++++

 [[jdt-java-editor]]
 === Java Editor

 ==== Open Implementation of selected Type

 The *Open Implementation* hyperlink and the *Navigate > Open
 Implementation* action now open the implementation of the selected
 interface or class also. In the past, *Open Implementation* was only
 available for methods.

 image::images/open-implementation-of-type.png[image]

 The hyperlink popup shows up when you hold *Ctrl* (on the Mac:
 **Command**), unless you've changed the modifier on the *Hyperlinking*
 preference page.

 ==== Automatically insert Braces at correct position

 The *Java > Editor > Typing > Automatically insert at correct position > Braces* preference option is now enabled by default. This will automatically insert the braces where they are required.

 image::images/auto-insert-braces.png[image]

 ==== Escape text when pasting into a string literal

 The *Java > Editor > Typing > Escape text when pasting into a string literal* preference option is now enabled by default. This will escape the special characters in pasted strings when they are pasted into an existing string literal.

 image::images/escape-text-when-pasting.png[image]

 To paste without escaping, you can either paste outside of a string
 literal, or you can disable *Edit* menu **> Smart Insert Mode**.

 ==== Quick Fix to move type annotations

 The rules for the placement of Java 8 "type annotations" introduced via
 JSR 308 are sometimes surprising. In case of errors, a new Quick Fix
 *Move type annotation* is offered, that moves the type annotation to a
 location that corresponds to what was probably intended.

 image::images/quickfix-move-type-annotation.png[image]

 ==== Defaults for annotation type elements in Javadoc

 The default value of an annotation type element is now shown in the
 *Javadoc* view and hover.

 image::images/defaults-for-annotation-type-elements-in-javadoc.png[image]

 ==== Set colors for Javadoc

 You can use the new color preferences to set the foreground text color
 and the background color in the *Javadoc* view and hovers:

 image::images/javadoc-colors.png[image]

 ==== Consistent Javadoc colors usage under Linux

 The Javadoc color usage on Linux was inconsistent since GTK 3.04. This
 has been resolved and support for Javadoc on the Eclipse Dark Theme has
 been added.

 Before:

 image::images/javadocbefore.png[image]

 After:

 image::images/javadocafter.png[image]

 Dark theme support:

 image::images/javadocdarktheme.png[image]

 [[jdt-java-views-and-dialogs]]
 === Java Views and Dialogs

 ==== Skip button in Organize Imports dialog

 While using the *Organize Imports* dialog to import multiple unresolved
 types, you can now skip a type without cancelling the whole operation by
 using the new *Skip* button. No import statement is added for the
 skipped type.

 image::images/skip-button-in-organize-imports-dialog.png[image]

 ==== Hide inherited members from java.lang.Object

 You can hide all inherited members from `java.lang.Object` in the *Quick
 Outline* (**Ctrl+O**) by using the new filter from the drop-down menu
 (**Ctrl+F10**):

 image::images/hide-inherited-object-members.png[image]

 ==== Hide deprecated fields and methods

 You can now hide the deprecated fields and methods in *Outline* view,
 *Members* view, *Package Explorer* view, *Project Explorer* view, and
 *Quick Outline* by using the new filter from their drop-down menu
 (**Ctrl+F10**):

 image::images/hide-deprecated-fields-and-methods.png[image]

 ==== Group by Project in Search view

 The default grouping of Java search results in the *Search* view has
 been changed to Group by Project. Earlier the results were grouped by
 package.

 image::images/group-by-project-in-search-view.png[image]

 You can use the buttons in the view tool bar to Group by Project,
 Package, File, or Type.

 ==== Type name with extension in New Java Type creation wizards

 New Java Type creation wizards now accept the `.java` extension with the
 type name instead of showing the error message: "Type name must not be
 qualified". For example, to create a new class `com.test.C1<T>.java`,
 you can directly paste this qualified type name with extension in the
 Name field of the New Java Class wizard.

 image::images/type-name-with-extension.png[image]

 ==== HiDPI JDT icons

 Composite icons such as Java element icons with modifier overlays are
 now rendered in high resolution in environments that support HiDPI
 images.

 image::images/jdt-composite-images-hidpi.png[image,width=479]

 [[jdt-java-compiler]]
 === Java Compiler

 ==== New Java index

 Eclipse 4.7 contains an experimental new Java index which is disabled by
 default. +
 As a thumb rule, you can try the new indexing to get better performance
 when there are a large number of Jar dependencies. The new index has
 been adopted completely in the *Type Hierarchy* view and partially in
 some features that use the binary file caching (jars and .class files)
 such as *Package Explorer* expansion for jars. It hasn't been adopted by
 the search features.

 You can enable the new index from **Preferences > Java**:

 image::images/new-java-index.png[image]

 To improve performance, the new index captures a lot of semantic
 information in an index file separate from the classic index file,
 consuming additional memory and disk space. The new *Rebuild Index*
 button can be used to delete the existing index files - both classic as
 well as new - then rebuild these index files from scratch. If *Enable
 new Java index* option is not checked, only the classic index file will
 be rebuilt though both will be deleted, thus saving disk space. Also, if
 index corruption is suspected, *Rebuild Index* can be used to start from
 a clean slate again.

 ==== Pass compiler options to annotation processors

 You can now pass compiler options to annotation processors using
 `%variable%` syntax in **Project > Properties > Java Compiler >
 Annotation Processing**.

 image::images/jdt-apt-processor-option-variables.png[image]

 This allows processors to compile Java sources using the Java project's
 settings without manually maintaining this information in the processor
 options.

 ==== Warnings for unlikely argument types

 Many developers have learned the hard way, that certain uses of Java
 collections that pass the compiler's type check, may still contain "type
 errors", resulting in unexpected runtime behaviour. A new analysis has
 been added to the Eclipse compiler for Java that will detect the most
 common bugs in this area.

 The common reason behind this problem is the fact that not all methods
 of those collection types make use of generics in the way one might
 expect. As a result it is possible to create a `Set<Short>`, whose
 `add(Short)` method will only accept arguments of type `Short`, yet
 method `remove(Object)` will happily accept literally any argument,
 because the method's parameter has type `Object`.

 Here is a code snippet that seems to add and remove the same element
 from the set, but at a closer look the `remove` call has no effect. What
 is difficult to see for the naked eye is now flagged by a new warning:

 image::images/unlikely1-basic.png[]

 In a simple world, this would be all there is to say, but over time
 people have developed various code patterns that rely on these overly
 general signatures. Consider the following use of subtyping:

 image::images/unlikely2-number-allowed.png[image]

 Depending on your coding style this may or may not be accepted as a
 legitimate short hand for: +
 `if (n instanceof Short) set.remove((Short) n);` +
 To reduce the churn caused by the new analysis, we developed some
 heuristics that filter out cases where types are "sufficiently similar",
 so the above goes unwarned.

 As with any heuristic, there is no clear line. This implies that the
 compiler may show "unwanted" warnings, or filter out invocations that
 are in fact bugs. For the former case,
 `@SuppressWarnings("unlikely-arg-type")` will document the exception
 both for the user and for the compiler. For the latter case, we provide
 an option to tighten the rules, namely to apply strict type
 compatibility checks instead of said heuristics. For this extra scrutiny
 you may enable the sub-option *Perform strict analysis against the
 expected type* in **Preferences > Java > Compiler > Errors/Warnings >
 Potential programming problems**.

 image::images/unlikely3-options.png[Preference options]

 Similarly, a check with default severity "Info" is offered for unlikely
 invocations of `java.lang.Object.equals(Object)` and
 `java.util.Objects.equals(Object,Object)`.

 image::images/unlikely5-equals.png[]

 [[jdt-java-formatter]]
 === Java Formatter

 ==== New way to count comment width

 A new option has been added in the code formatter profile editor that
 makes the formatter count a comment's width from its starting position
 instead of the beginning of the line.

 You can change this option in the *Java > Code Style > Formatter*
 preferences in the *Comments* tab, under **Line width**.

 image::images/formatter-comment-width-ui.png[image]

 image::images/formatter-comment-width-preview.png[image]

 This option allows more space for comments in heavily indented blocks of
 code and for line comments added to the right of some code. And at the
 same time, it keeps comments that start at the beginning of the line
 from getting too wide and uncomfortable to read.

 [[jdt-debug]]
 === Debug

 ==== Method result after step operations

 During debugging, the last method result (per return or throw) that was
 observed during **Step Into**, *Step Over* or **Step Return**, is shown
 as first line in the *Variables* view.

 image::images/step-show-methodresult.png[image]

 This can be disabled with the new option *Preferences > Java > Debug >
 Show method result after a step operation (if supported by the VM; may
 be slow)*

 ==== Triggers for breakpoints

 You can now define a set of triggers for the breakpoints in a workspace.

 image::images/trigger-breakpoint-properties.png[image]

 Any breakpoint can be set as a trigger point by using *Breakpoint
 Properties...* dialog or the *Breakpoints* view's detail pane.

 image::images/trigger-breakpoint-view-ruler.png[image]

 Triggers will be rendered with an overlay of "T" and the breakpoints
 suppressed by the triggers will be rendered with an overlay of "T" with
 a cut.

 All the other breakpoints that are initially suppressed by triggers will
 be hit only after any of the trigger points has been hit. All the
 triggers are disabled after a trigger point is hit and will be
 re-enabled after the run.

 ==== Conditional watchpoint

 Like for line breakpoints, conditions can now also be added to
 **Watchpoints**, where the old value of the field can be used as part of
 the condition.

 image::images/watchpoint-condition.png[image]

 Toggle Tracepoint

 A new action *Run > Toggle Tracepoint* has been added.

 image::images/toggle-trace-point-run.png[image]

 The action creates a conditional breakpoint using the "systrace"
 template, which prints the class and method name.

 image::images/toggle-trace-point-conditional-breakpoint.png[image]

 This makes use of another new feature of conditional breakpoints: As
 long as the condition doesn't explicitly return a boolean `true`, the
 condition is now considered to implicitly return false, and the
 breakpoint will not suspend execution.

 ==== Show Logical Structure enabled by default

 In the *Variables* view, *Show Logical Structure* is now enabled by
 default. E.g. collection objects now directly show their contained
 elements instead of their internal structure.

 image::images/jdt-debug-show-logical-structure-by-default.png[image]

 The *Show Logical Structure* context menu lets you choose or edit the
 representation.

 image::images/jdt-debug-edit-logical-structure-context-menu.png[image]

 ==== Remote Java Application "Socket Listen" type supports multiple incoming
 connections

 The *Remote Java Application* debug configuration's *Standard (Socket
 Listen)* connection type now supports incoming connections from multiple
 VMs. This is useful for debugging distributed systems. The connection
 limit may be set to a fixed number, or `0` for unlimited connections.

 image::images/remote-java-listen-conn-limit.png[image]

 ==== New option to disable Hot Code Replace

 You can now disable
 https://wiki.eclipse.org/FAQ_What_is_hot_code_replace%3F[Hot Code
 Replace (HCR)] if it causes any trouble or if you want to avoid code
 changes in a debug target. HCR is enabled by default but can be disabled
 in **Preferences > Java > Debug**.

 image::images/option-disable-hcr.png[image]

 [[jdt-junit]]
 === JUnit

 ==== Show JUnit failure trace in Console view

 A new button has been added to the JUnit Failure Trace header to show
 the stack trace of a failed JUnit test in the *Console* view. The
 Console view makes it convenient to view a long and wide stack trace,
 copy parts of the stack trace and navigate to the classes on the stack
 trace using hyperlinks.

 image::images/show-junit-failure-trace-in-console-view.png[image]
	[[jdt-java-development-tools]]
	== Java development tools

	[[jdt-java-java9]]
	=== Java 9

	==== Support for Building Java 9 Applications

	The Java™ 9 specification has not been released yet and so support has not yet been integrated into our standard download packages. You can add an early access preview to the Eclipse IDE, Oxygen Edition (4.7).

	The Eclipse Java™ 9 Support (BETA) contains the following:

	* ability to add JRE and JDK 9 as installed JRE;
	* support for JavaSE-9 execution environment;
	* ability to create Java and Plug-in projects that use a JRE or JDK 9; and
	* ability to compile modules that are part of a Java project

	[NOTE]
	====
	This is an implementation of an early-draft specification developed under the Java Community Process (JCP) and is made available for testing and evaluation purposes only. The code is not compatible with any specification of the JCP.
	====

	For up-to-date information, please see https://marketplace.eclipse.org/content/java-9-support-beta-oxygen[Java 9 Support (BETA) for Oxygen] in the Eclipse Marketplace.

	Install the beta by dragging the install button onto your running Eclipse IDE, Oxygen Edition instance.

	++++
	<div style="text-align:center">
	<a href="http://marketplace.eclipse.org/marketplace-client-intro?mpc_install=2393593" class="drag" title="Drag to your running Eclipse* workspace. Requires Eclipse Marketplace Client"><img class="img-responsive" src="https://marketplace.eclipse.org/sites/all/themes/solstice/public/images/marketplace/btn-install.png" alt="Drag to your running Eclipse workspace. *Requires Eclipse Marketplace Client" /></a>
	</div>
	++++

	[[jdt-java-editor]]
	=== Java Editor

	==== Open Implementation of selected Type

	The Open Implementation hyperlink and the *Navigate > Open
	Implementation* action now open the implementation of the selected
	interface or class also. In the past, Open Implementation was only
	available for methods.

	image::images/open-implementation-of-type.png[image]

	The hyperlink popup shows up when you hold Ctrl (on the Mac:
	Command), unless you've changed the modifier on the Hyperlinking
	preference page.

	==== Automatically insert Braces at correct position

	The Java > Editor > Typing > Automatically insert at correct position > Braces preference option is now enabled by default. This will automatically insert the braces where they are required.

	image::images/auto-insert-braces.png[image]

	==== Escape text when pasting into a string literal

	The Java > Editor > Typing > Escape text when pasting into a string literal preference option is now enabled by default. This will escape the special characters in pasted strings when they are pasted into an existing string literal.

	image::images/escape-text-when-pasting.png[image]

	To paste without escaping, you can either paste outside of a string
	literal, or you can disable Edit menu > Smart Insert Mode.

	==== Quick Fix to move type annotations

	The rules for the placement of Java 8 "type annotations" introduced via
	JSR 308 are sometimes surprising. In case of errors, a new Quick Fix
	Move type annotation is offered, that moves the type annotation to a
	location that corresponds to what was probably intended.

	image::images/quickfix-move-type-annotation.png[image]

	==== Defaults for annotation type elements in Javadoc

	The default value of an annotation type element is now shown in the
	Javadoc view and hover.

	image::images/defaults-for-annotation-type-elements-in-javadoc.png[image]

	==== Set colors for Javadoc

	You can use the new color preferences to set the foreground text color
	and the background color in the Javadoc view and hovers:

	image::images/javadoc-colors.png[image]

	==== Consistent Javadoc colors usage under Linux

	The Javadoc color usage on Linux was inconsistent since GTK 3.04. This
	has been resolved and support for Javadoc on the Eclipse Dark Theme has
	been added.

	Before:

	image::images/javadocbefore.png[image]

	After:

	image::images/javadocafter.png[image]

	Dark theme support:

	image::images/javadocdarktheme.png[image]

	[[jdt-java-views-and-dialogs]]
	=== Java Views and Dialogs

	==== Skip button in Organize Imports dialog

	While using the Organize Imports dialog to import multiple unresolved
	types, you can now skip a type without cancelling the whole operation by
	using the new Skip button. No import statement is added for the
	skipped type.

	image::images/skip-button-in-organize-imports-dialog.png[image]

	==== Hide inherited members from java.lang.Object

	You can hide all inherited members from `java.lang.Object` in the *Quick
	Outline* (Ctrl+O) by using the new filter from the drop-down menu
	(Ctrl+F10):

	image::images/hide-inherited-object-members.png[image]

	==== Hide deprecated fields and methods

	You can now hide the deprecated fields and methods in Outline view,
	Members view, Package Explorer view, Project Explorer view, and
	Quick Outline by using the new filter from their drop-down menu
	(Ctrl+F10):

	image::images/hide-deprecated-fields-and-methods.png[image]

	==== Group by Project in Search view

	The default grouping of Java search results in the Search view has
	been changed to Group by Project. Earlier the results were grouped by
	package.

	image::images/group-by-project-in-search-view.png[image]

	You can use the buttons in the view tool bar to Group by Project,
	Package, File, or Type.

	==== Type name with extension in New Java Type creation wizards

	New Java Type creation wizards now accept the `.java` extension with the
	type name instead of showing the error message: "Type name must not be
	qualified". For example, to create a new class `com.test.C1<T>.java`,
	you can directly paste this qualified type name with extension in the
	Name field of the New Java Class wizard.

	image::images/type-name-with-extension.png[image]

	==== HiDPI JDT icons

	Composite icons such as Java element icons with modifier overlays are
	now rendered in high resolution in environments that support HiDPI
	images.

	image::images/jdt-composite-images-hidpi.png[image,width=479]

	[[jdt-java-compiler]]
	=== Java Compiler

	==== New Java index

	Eclipse 4.7 contains an experimental new Java index which is disabled by
	default. +
	As a thumb rule, you can try the new indexing to get better performance
	when there are a large number of Jar dependencies. The new index has
	been adopted completely in the Type Hierarchy view and partially in
	some features that use the binary file caching (jars and .class files)
	such as Package Explorer expansion for jars. It hasn't been adopted by
	the search features.

	You can enable the new index from Preferences > Java:

	image::images/new-java-index.png[image]

	To improve performance, the new index captures a lot of semantic
	information in an index file separate from the classic index file,
	consuming additional memory and disk space. The new Rebuild Index
	button can be used to delete the existing index files - both classic as
	well as new - then rebuild these index files from scratch. If *Enable
	new Java index* option is not checked, only the classic index file will
	be rebuilt though both will be deleted, thus saving disk space. Also, if
	index corruption is suspected, Rebuild Index can be used to start from
	a clean slate again.

	==== Pass compiler options to annotation processors

	You can now pass compiler options to annotation processors using
	`%variable%` syntax in **Project > Properties > Java Compiler >
	Annotation Processing**.

	image::images/jdt-apt-processor-option-variables.png[image]

	This allows processors to compile Java sources using the Java project's
	settings without manually maintaining this information in the processor
	options.

	==== Warnings for unlikely argument types

	Many developers have learned the hard way, that certain uses of Java
	collections that pass the compiler's type check, may still contain "type
	errors", resulting in unexpected runtime behaviour. A new analysis has
	been added to the Eclipse compiler for Java that will detect the most
	common bugs in this area.

	The common reason behind this problem is the fact that not all methods
	of those collection types make use of generics in the way one might
	expect. As a result it is possible to create a `Set<Short>`, whose
	`add(Short)` method will only accept arguments of type `Short`, yet
	method `remove(Object)` will happily accept literally any argument,
	because the method's parameter has type `Object`.

	Here is a code snippet that seems to add and remove the same element
	from the set, but at a closer look the `remove` call has no effect. What
	is difficult to see for the naked eye is now flagged by a new warning:

	image::images/unlikely1-basic.png[]

	In a simple world, this would be all there is to say, but over time
	people have developed various code patterns that rely on these overly
	general signatures. Consider the following use of subtyping:

	image::images/unlikely2-number-allowed.png[image]

	Depending on your coding style this may or may not be accepted as a
	legitimate short hand for: +
	`if (n instanceof Short) set.remove((Short) n);` +
	To reduce the churn caused by the new analysis, we developed some
	heuristics that filter out cases where types are "sufficiently similar",
	so the above goes unwarned.

	As with any heuristic, there is no clear line. This implies that the
	compiler may show "unwanted" warnings, or filter out invocations that
	are in fact bugs. For the former case,
	`@SuppressWarnings("unlikely-arg-type")` will document the exception
	both for the user and for the compiler. For the latter case, we provide
	an option to tighten the rules, namely to apply strict type
	compatibility checks instead of said heuristics. For this extra scrutiny
	you may enable the sub-option *Perform strict analysis against the
	expected type* in **Preferences > Java > Compiler > Errors/Warnings >
	Potential programming problems**.

	image::images/unlikely3-options.png[Preference options]

	Similarly, a check with default severity "Info" is offered for unlikely
	invocations of `java.lang.Object.equals(Object)` and
	`java.util.Objects.equals(Object,Object)`.

	image::images/unlikely5-equals.png[]

	[[jdt-java-formatter]]
	=== Java Formatter

	==== New way to count comment width

	A new option has been added in the code formatter profile editor that
	makes the formatter count a comment's width from its starting position
	instead of the beginning of the line.

	You can change this option in the Java > Code Style > Formatter
	preferences in the Comments tab, under Line width.

	image::images/formatter-comment-width-ui.png[image]

	image::images/formatter-comment-width-preview.png[image]

	This option allows more space for comments in heavily indented blocks of
	code and for line comments added to the right of some code. And at the
	same time, it keeps comments that start at the beginning of the line
	from getting too wide and uncomfortable to read.

	[[jdt-debug]]
	=== Debug

	==== Method result after step operations

	During debugging, the last method result (per return or throw) that was
	observed during Step Into, Step Over or Step Return, is shown
	as first line in the Variables view.

	image::images/step-show-methodresult.png[image]

	This can be disabled with the new option *Preferences > Java > Debug >
	Show method result after a step operation (if supported by the VM; may
	be slow)*

	==== Triggers for breakpoints

	You can now define a set of triggers for the breakpoints in a workspace.

	image::images/trigger-breakpoint-properties.png[image]

	Any breakpoint can be set as a trigger point by using *Breakpoint
	Properties...* dialog or the Breakpoints view's detail pane.

	image::images/trigger-breakpoint-view-ruler.png[image]

	Triggers will be rendered with an overlay of "T" and the breakpoints
	suppressed by the triggers will be rendered with an overlay of "T" with
	a cut.

	All the other breakpoints that are initially suppressed by triggers will
	be hit only after any of the trigger points has been hit. All the
	triggers are disabled after a trigger point is hit and will be
	re-enabled after the run.

	==== Conditional watchpoint

	Like for line breakpoints, conditions can now also be added to
	Watchpoints, where the old value of the field can be used as part of
	the condition.

	image::images/watchpoint-condition.png[image]

	Toggle Tracepoint

	A new action Run > Toggle Tracepoint has been added.

	image::images/toggle-trace-point-run.png[image]

	The action creates a conditional breakpoint using the "systrace"
	template, which prints the class and method name.

	image::images/toggle-trace-point-conditional-breakpoint.png[image]

	This makes use of another new feature of conditional breakpoints: As
	long as the condition doesn't explicitly return a boolean `true`, the
	condition is now considered to implicitly return false, and the
	breakpoint will not suspend execution.

	==== Show Logical Structure enabled by default

	In the Variables view, Show Logical Structure is now enabled by
	default. E.g. collection objects now directly show their contained
	elements instead of their internal structure.

	image::images/jdt-debug-show-logical-structure-by-default.png[image]

	The Show Logical Structure context menu lets you choose or edit the
	representation.

	image::images/jdt-debug-edit-logical-structure-context-menu.png[image]

	==== Remote Java Application "Socket Listen" type supports multiple incoming
	connections

	The Remote Java Application debug configuration's *Standard (Socket
	Listen)* connection type now supports incoming connections from multiple
	VMs. This is useful for debugging distributed systems. The connection
	limit may be set to a fixed number, or `0` for unlimited connections.

	image::images/remote-java-listen-conn-limit.png[image]

	==== New option to disable Hot Code Replace

	You can now disable
	https://wiki.eclipse.org/FAQ_What_is_hot_code_replace%3F[Hot Code
	Replace (HCR)] if it causes any trouble or if you want to avoid code
	changes in a debug target. HCR is enabled by default but can be disabled
	in Preferences > Java > Debug.

	image::images/option-disable-hcr.png[image]

	[[jdt-junit]]
	=== JUnit

	==== Show JUnit failure trace in Console view

	A new button has been added to the JUnit Failure Trace header to show
	the stack trace of a failed JUnit test in the Console view. The
	Console view makes it convenient to view a long and wide stack trace,
	copy parts of the stack trace and navigate to the classes on the stack
	trace using hyperlinks.

	image::images/show-junit-failure-trace-in-console-view.png[image]