diff -r 5329b63a56e5 api.debugger/apichanges.xml
--- a/api.debugger/apichanges.xml	Fri Jan 15 13:54:43 2010 +0100
+++ b/api.debugger/apichanges.xml	Thu Jan 21 18:50:47 2010 +0100
@@ -364,6 +364,24 @@
         <issue number="178301"/>
     </change>
 
+    <change id="BreakpointsGrouping">
+        <api name="DebuggerCoreAPI"/>
+        <summary>Breakpoints group properties.</summary>
+        <version major="1" minor="23"/>
+        <date day="28" month="1" year="2010"/>
+        <author login="mentlicher"/>
+        <compatibility binary="compatible" source="compatible" addition="yes"/>
+        <description>
+             <p>
+             Add Breakpoint.getGroupProperties() method, that returns an implementation
+             of GroupProperties class with the relevant grouping information
+             used by BreakpointsWindow to create hierarchy of breakpoint groups
+             </p>
+        </description>
+        <class package="org.netbeans.api.debugger" name="Breakpoint" />
+        <issue number="179759"/>
+    </change>
+
 </changes>
 
   <!-- Now the surrounding HTML text and document structure: -->
diff -r 5329b63a56e5 api.debugger/manifest.mf
--- a/api.debugger/manifest.mf	Fri Jan 15 13:54:43 2010 +0100
+++ b/api.debugger/manifest.mf	Thu Jan 21 18:50:47 2010 +0100
@@ -1,5 +1,5 @@
 Manifest-Version: 1.0
 OpenIDE-Module: org.netbeans.api.debugger/1
 OpenIDE-Module-Localizing-Bundle: org/netbeans/api/debugger/Bundle.properties
-OpenIDE-Module-Specification-Version: 1.22
+OpenIDE-Module-Specification-Version: 1.23
 OpenIDE-Module-Layer: org/netbeans/api/debugger/layer.xml
diff -r 5329b63a56e5 api.debugger/nbproject/project.xml
--- a/api.debugger/nbproject/project.xml	Fri Jan 15 13:54:43 2010 +0100
+++ b/api.debugger/nbproject/project.xml	Thu Jan 21 18:50:47 2010 +0100
@@ -47,6 +47,15 @@
             <code-name-base>org.netbeans.api.debugger</code-name-base>
             <module-dependencies>
                 <dependency>
+                    <code-name-base>org.netbeans.modules.projectapi</code-name-base>
+                    <build-prerequisite/>
+                    <compile-dependency/>
+                    <run-dependency>
+                        <release-version>1</release-version>
+                        <specification-version>1.28</specification-version>
+                    </run-dependency>
+                </dependency>
+                <dependency>
                     <code-name-base>org.openide.filesystems</code-name-base>
                     <build-prerequisite/>
                     <compile-dependency/>
diff -r 5329b63a56e5 api.debugger/src/org/netbeans/api/debugger/Breakpoint.java
--- a/api.debugger/src/org/netbeans/api/debugger/Breakpoint.java	Fri Jan 15 13:54:43 2010 +0100
+++ b/api.debugger/src/org/netbeans/api/debugger/Breakpoint.java	Thu Jan 21 18:50:47 2010 +0100
@@ -43,6 +43,8 @@
 
 import java.beans.PropertyChangeListener;
 import java.beans.PropertyChangeSupport;
+import org.netbeans.api.project.Project;
+import org.openide.filesystems.FileObject;
 
 /**
  * Abstract definition of breakpoint.
@@ -58,6 +60,9 @@
     public static final String          PROP_DISPOSED = "disposed"; // NOI18N
     /** Property name for name of group of the breakpoint. */
     public static final String          PROP_GROUP_NAME = "groupName"; // NOI18N
+    /** Property name for other group properties of the breakpoint. 
+     * @since 1.23 */
+    public static final String          PROP_GROUP_PROPERTIES = "groupProperties"; // NOI18N
     /** Property name for breakpoint validity */
     public static final String          PROP_VALIDITY = "validity"; // NOI18N
     /** Property name constant. */
@@ -187,16 +192,39 @@
         }
         firePropertyChange(PROP_HIT_COUNT_FILTER, old, newProp);
     }
-    
+
+    /**
+     * Get the name of a user-created group for this breakpoint.
+     */
     public String getGroupName () {
         return groupName;
     }
     
+    /**
+     * Set the name of a user-created group for this breakpoint.
+     */
     public void setGroupName (String newGroupName) {
         if (groupName.equals (newGroupName)) return;
         String old = groupName;
         groupName = newGroupName.intern();
         firePropertyChange (PROP_GROUP_NAME, old, newGroupName);
+    }
+
+    /**
+     * Get group properties of the breakpoint.
+     * These are implementation-defined group properties as oposed to {@link #getGroupName()},
+     * which returns user-defined group name.
+     * <p>
+     * These properties are used by the Breakpoint Window to show a tree
+     * hierarchy of groups and associated breakpoints.
+     * Implementation should fire {@link #PROP_GROUP_PROPERTIES} event when
+     * the group properties change.
+     * @return {@link GroupProperties} or <code>null</code> when no group properties
+     * are defined.
+     * @since 1.23
+     */
+    public GroupProperties getGroupProperties() {
+        return null;
     }
     
     /** 
@@ -263,4 +291,49 @@
         dispose ();
         firePropertyChange (PROP_DISPOSED, Boolean.FALSE, Boolean.TRUE);
     }
+
+    /**
+     * Group properties of breakpoint.
+     * These are used by the Breakpoint Window to show a tree hierarchy of
+     * groups and associated breakpoints.
+     * @since 1.23
+     */
+    public static abstract class GroupProperties {
+
+        /**
+         * Get the language of the source file with the breakpoint.
+         * @return The human-readable language of the breakpoint source file or <code>null</code>
+         * when this does not apply.
+         * @see <code>org.netbeans.spi.debugger.ui.BreakpointType.getCategoryDisplayName()</code>
+         */
+        public abstract String getLanguage();
+
+        /**
+         * Get the breakpoint type.
+         * @return The human-readable type of the breakpoint or <code>null</code>
+         * when this does not apply.
+         * @see <code>org.netbeans.spi.debugger.ui.BreakpointType.getTypeDisplayName()</code>
+         */
+        public abstract String getType();
+
+        /**
+         * Get the source files containing this breakpoint.
+         * @return The source files where this breakpoint is submitted or <code>null</code>
+         * when this does not apply.
+         */
+        public abstract FileObject[] getFiles();
+
+        /**
+         * Get the projects containing this breakpoint.
+         * @return The projects in which this breakpoint is submitted or <code>null</code>
+         * when this does not apply.
+         */
+        public abstract Project[] getProjects();
+
+        /**
+         * Test is this breakpoint is hidden (not visible to the user).
+         * @return <code>true</code> when this breakpoint is hidden, <code>false</code> otherwise.
+         */
+        public abstract boolean isHidden();
+    }
 }