Product Version: NetBeans IDE 7.3 (Build 201302132200)
Java: 1.8.0-ea; Java HotSpot(TM) 64-Bit Server VM 25.0-b20
Runtime: Java(TM) SE Runtime Environment 1.8.0-ea-b79
System: Mac OS X version 10.8.2 running on x86_64; US-ASCII; en_US (nb)
User directory: /Users/tomas/Library/Application Support/NetBeans/7.3
Cache directory: /Users/tomas/Library/Caches/NetBeans/7.3
---------------
- created j2se project (default jdk is 8)
- clean and build -> fails:

ant -f /Users/tomas/NetBeansProjects/JavaApplication1 clean jar
init:
deps-clean:
Updating property file: /Users/tomas/NetBeansProjects/JavaApplication1/build/built-clean.properties
Deleting directory /Users/tomas/NetBeansProjects/JavaApplication1/build
clean:
init:
deps-jar:
Created dir: /Users/tomas/NetBeansProjects/JavaApplication1/build
Updating property file: /Users/tomas/NetBeansProjects/JavaApplication1/build/built-jar.properties
Created dir: /Users/tomas/NetBeansProjects/JavaApplication1/build/classes
Created dir: /Users/tomas/NetBeansProjects/JavaApplication1/build/empty
Created dir: /Users/tomas/NetBeansProjects/JavaApplication1/build/generated-sources/ap-source-output
/Users/tomas/NetBeansProjects/JavaApplication1/nbproject/build-impl.xml:926: The following error occurred while executing this line:
/Users/tomas/NetBeansProjects/JavaApplication1/nbproject/build-impl.xml:268: Class not found: javac1.8
BUILD FAILED (total time: 0 seconds)

verbose output shows exception:

/Users/tomas/NetBeansProjects/JavaApplication1/nbproject/build-impl.xml:926: The following error occurred while executing this line:
/Users/tomas/NetBeansProjects/JavaApplication1/nbproject/build-impl.xml:268: Class not found: javac1.8
	at org.apache.tools.ant.util.ClasspathUtils.newInstance(ClasspathUtils.java:257)
	at org.apache.tools.ant.taskdefs.compilers.CompilerAdapterFactory.resolveClassName(CompilerAdapterFactory.java:194)
	at org.apache.tools.ant.taskdefs.compilers.CompilerAdapterFactory.getCompiler(CompilerAdapterFactory.java:155)
	at org.apache.tools.ant.taskdefs.Javac.findSupportedFileExtensions(Javac.java:979)
	at org.apache.tools.ant.taskdefs.Javac.scanDir(Javac.java:956)
	at org.apache.tools.ant.taskdefs.Javac.execute(Javac.java:927)
	at org.netbeans.modules.java.source.ant.JavacTask.execute(JavacTask.java:145)
	at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:291)
	at sun.reflect.GeneratedMethodAccessor261.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:487)
	at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
	at org.apache.tools.ant.Task.perform(Task.java:348)
	at org.apache.tools.ant.taskdefs.Sequential.execute(Sequential.java:68)
	at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:291)
	at sun.reflect.GeneratedMethodAccessor261.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:487)
	at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
	at org.apache.tools.ant.Task.perform(Task.java:348)
	at org.apache.tools.ant.taskdefs.MacroInstance.execute(MacroInstance.java:398)
	at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:291)
	at sun.reflect.GeneratedMethodAccessor261.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:487)
	at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
	at org.apache.tools.ant.Task.perform(Task.java:348)
	at org.apache.tools.ant.Target.execute(Target.java:392)
	at org.apache.tools.ant.Target.performTasks(Target.java:413)
	at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1399)
	at org.apache.tools.ant.Project.executeTarget(Project.java:1368)
	at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:41)
	at org.apache.tools.ant.Project.executeTargets(Project.java:1251)
	at org.apache.tools.ant.module.bridge.impl.BridgeImpl.run(BridgeImpl.java:283)
	at org.apache.tools.ant.module.run.TargetExecutor.run(TargetExecutor.java:541)
	at org.netbeans.core.execution.RunClassThread.run(RunClassThread.java:153)
Caused by: java.lang.ClassNotFoundException: javac1.8
	at org.apache.tools.ant.AntClassLoader.findClassInComponents(AntClassLoader.java:1365)
	at org.apache.tools.ant.AntClassLoader.findClass(AntClassLoader.java:1315)
	at org.apache.tools.ant.AntClassLoader.loadClass(AntClassLoader.java:1068)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
	at java.lang.Class.forName0(Native Method)
	at java.lang.Class.forName(Class.java:263)
	at org.apache.tools.ant.util.ClasspathUtils.newInstance(ClasspathUtils.java:249)
	... 35 more 


Running from command line (after setting JAVA_HOME to 1.8):
1) by default Ant (1.8.2) on my 10.8.2 - OK
2) by IDE's bundles Ant (1.8.4) - the same error