StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

PO
text
Body
copied!<p>None of the answers so far are correct and this is the first hit that comes up on Google if you query the error mentioned, so I feel some clarification is needed.</p> <p>JVMTI and JDWP <em>do</em> work together, in fact they generally must be used together. You will get <code>ERROR: JDWP unable to get necessary JVMTI capabilities</code> if <code>-Xrunjdwp</code> (and/or possibly <code>-agentlib:jdwp</code>) is specified more than once on the command line. To fix it, make sure you only have one of <code>-Xrunjdwp</code> or <code>-agentlib:jdwp</code> in your command line. </p> <p>For more details, read on...</p> <p>JVMTI (Java Virtual Machine Tool Interface) is the successor to JVMDI (Java Virtual Machine Debug Interface) and JVMPI (Java Virtual Machine Profiling Interface). It incorporates the functionality of both JVMDI and JVMPI, both of which were deprecated in Java 5 and removed in Java 6. It is the API that exposes the internals of the JVM for the purposes of debugging and profiling.</p> <p>JDWP (Java Debug Wire Protocol) is a protocol that describes a simple mechanism for transmitting commands and responses. As far as I know, it is the only way for a debugger sitting outside the JVM to communicate with it and to interface with the JVMTI. </p> <p>JDI (Java Debugger Interface) is a client-side (debugger-side) API which exposes some of the features of JVMTI while making use of JDWP more or less transparently. </p> <p>The <a href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6354345" rel="noreferrer" title="bug">bug</a> mentioned in Bob Dobbs's answer concerns the misleading error message, and the fact that the JVM will try to load JDWP once for every time it is specified on the command line. It doesn't state anywhere that JDWP and JVMTI cannot be used together.</p> <p>More info here: <a href="http://publib.boulder.ibm.com/infocenter/iseries/v5r4/topic/rzaha/jpdebuga.htm" rel="noreferrer">http://publib.boulder.ibm.com/infocenter/iseries/v5r4/topic/rzaha/jpdebuga.htm</a></p>

Querying!

Guidance

An individual column

Larger individual text columns get their own page to allow for proper reading.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload