The packages can be overrided by Java Endorsed Standards

Endorsed Standards APIs

The Endorsed Standards for Java SE constitute all classes and interfaces that are defined in the packages listed in this section. Classes and interfaces defined in sub-packages of listed packages are not Endorsed Standards unless those sub-packages are themselves
listed. The Endorsed Standards Override Mechanism may be used to override the Java SE platform packages in this list, and these packages may be overridden only by versions of the Endorsed Standard that are newer than that provided by the Java platform as released
by Sun. With the exception of packages listed here and the technologies listed in the
Standalone Technologies section below, no other packages from the Java SE platform API specification may be overridden.

javax.rmi.CORBA
org.omg.CORBA
org.omg.CORBA.DynAnyPackage
org.omg.CORBA.ORBPackage
org.omg.CORBA.portable
org.omg.CORBA.TypeCodePackage
org.omg.CORBA_2_3
org.omg.CORBA_2_3.portable
org.omg.CosNaming
org.omg.CosNaming.NamingContextExtPackage
org.omg.CosNaming.NamingContextPackage
org.omg.Dynamic
org.omg.DynamicAny
org.omg.DynamicAny.DynAnyFactoryPackage
org.omg.DynamicAny.DynAnyPackage
org.omg.IOP
org.omg.IOP.CodecFactoryPackage
org.omg.IOP.CodecPackage
org.omg.Messaging
org.omg.PortableInterceptor
org.omg.PortableInterceptor.ORBInitInfoPackage
org.omg.PortableServer
org.omg.PortableServer.CurrentPackage
org.omg.PortableServer.POAManagerPackage
org.omg.PortableServer.POAPackage
org.omg.PortableServer.portable
org.omg.PortableServer.ServantLocatorPackage
org.omg.SendingContext
org.omg.stub.java.rmi
org.w3c.dom
org.xml.sax
org.xml.sax.ext
org.xml.sax.helpers

In addition to the packages listed above, which are part of the Java SE specification, users of Sun's Java SE Reference Implementation are allowed to use the Endorsed Standards Override Mechanism to override implementation-specific classes associated with
these packages, such as the org.w3c.dom sub-packages delivered in Sun's Reference Implementation.

Standalone Technologies

The Standalone Technologies for Java SE constitute all classes and interfaces that are defined and implemented in the technologies listed in this section. The Endorsed Standards Override Mechanism may be used to override the Java technologies in this list,
and these technologies may be overridden only by providing a complete and newer implementation of the Standalone Technology than was provided in the original implementation of the Java Platform. With the exception of the technologies in this list and the packages
listed in the Endorsed Standards APIs section above, no other packages from the Java SE platform API specification may be overridden.

Standalone Technology	JSR	Supported Implementation Version	Packages
Java API for XML Processing (JAXP)	JSR 206	1.6.0	See Java API for XML Processing in the Java SE Developer Guides.
Streaming API for XML (StAX)	JSR 173	1.3	`javax.xml.stream` `javax.xml.stream.events` `javax.xml.stream.util`
Java Architecture for XML Binding (JAXB)	JSR 222	2.2.8	`javax.xml.bind` `javax.xml.bind.annotation` `javax.xml.bind.annotation.adapters` `javax.xml.bind.attachment` `javax.xml.bind.helpers` `javax.xml.bind.util`
Java API for XML Web Services (JAX-WS)	JSR 224	2.2.9	`javax.xml.ws` `javax.xml.ws.handler` `javax.xml.ws.handler.soap` `javax.xml.ws.http` `javax.xml.ws.soap` `javax.xml.ws.spi` `javax.xml.ws.spi.http` `javax.xml.ws.wsaddressing`
Java Compiler API	JSR 199	1.8	`javax.tools`
Pluggable Annotation Processing API	JSR 269	1.8	`javax.annotation.processing` `javax.lang.model` `javax.lang.model.element` `javax.lang.model.type` `javax.lang.model.util`