When SA is attached to a process using attach(), detached using detach() and then re-attached to the same process using attach(), the second attach() call fails. On Windows, it fails with the following trace:

java.lang.RuntimeException: not attached to a process or Dr Watson dump
at sun.jvm.hotspot.debugger.windbg.WindbgDebuggerLocal.requireAttach(WindbgDebuggerLocal.java:438)
at sun.jvm.hotspot.debugger.windbg.WindbgDebuggerLocal.readBytesFromProcess(WindbgDebuggerLocal.java:484)
at sun.jvm.hotspot.debugger.DebuggerBase$Fetcher.fetchPage(DebuggerBase.java:76)
at sun.jvm.hotspot.debugger.PageCache.getPage(PageCache.java:178)
at sun.jvm.hotspot.debugger.PageCache.getInt(PageCache.java:96)
at sun.jvm.hotspot.debugger.DebuggerBase.readCInteger(DebuggerBase.java:355)
at sun.jvm.hotspot.debugger.DebuggerBase.readAddressValue(DebuggerBase.java:454)
at sun.jvm.hotspot.debugger.windbg.WindbgDebuggerLocal.readAddress(WindbgDebuggerLocal.java:316)
at sun.jvm.hotspot.debugger.windbg.WindbgAddress.getAddressAt(WindbgAddress.java:72)
at sun.jvm.hotspot.types.basic.BasicField.getAddress(BasicField.java:248)
at sun.jvm.hotspot.types.basic.BasicAddressFieldWrapper.getValue(BasicAddressFieldWrapper.java:48)
at sun.jvm.hotspot.memory.Universe.getHeapBase(Universe.java:104)
at sun.jvm.hotspot.runtime.VM.initialize(VM.java:345)
at sun.jvm.hotspot.HotSpotAgent.setupVM(HotSpotAgent.java:420)
Caused: sun.jvm.hotspot.debugger.DebuggerException
at sun.jvm.hotspot.HotSpotAgent.setupVM(HotSpotAgent.java:424)
at sun.jvm.hotspot.HotSpotAgent.go(HotSpotAgent.java:315)
at sun.jvm.hotspot.HotSpotAgent.attach(HotSpotAgent.java:158)