FULL PRODUCT VERSION :
java version "1.8.0_20"
Java(TM) SE Runtime Environment (build 1.8.0_20-b26)
Java HotSpot(TM) 64-Bit Server VM (build 25.20-b23, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Darwin gray.local 13.3.0 Darwin Kernel Version 13.3.0: Tue Jun 3 21:27:35 PDT 2014; root:xnu-2422.110.17~1/RELEASE_X86_64 x86_64

EXTRA RELEVANT SYSTEM CONFIGURATION :
I didn't use the installer, but extracted the .dmg file and copy the JDK into my user folder. The program is started via:
/Users/daniel/jdk1.8.0u20/bin/java -cp bin/ de.mmis.core.prototype.Prototype

A DESCRIPTION OF THE PROBLEM :
I'm using the Java VisualVM bundled with the current JDK (version: 1.8.0_20 (Build 1370-140407); platform 20140407-unknown-revn). When I start the CPU Profiler for my program I receive:

Profiler Agent: JNI OnLoad Initializing...
Profiler Agent: JNI OnLoad Initialized successfully
Profiler Agent: Waiting for connection on port 5140 (Protocol version: 14)
Profiler Agent: Established connection with the tool
Profiler Agent: Local accelerated session
Profiler Agent Error: Redefinition failed for classes:
[...]
java.lang.reflect.Method
Profiler Agent Error: with message: Redefinition failed with error 62
Check JVMTI documentation for this error code.
[...]
Debug: writing class file: java.lang.reflect.Method, into file: java.lang.reflect.Method.class

Connecting the same version of the VisualVM to my old Java installation works as expected and provides me with a profile.

REGRESSION. Last worked in version 8u5

ADDITIONAL REGRESSION INFORMATION:
java version "1.8.0_05"
Java(TM) SE Runtime Environment (build 1.8.0_05-b13)
Java HotSpot(TM) 64-Bit Server VM (build 25.5-b02, mixed mode)

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. compile and start a program with 1.8.0_05
2. connect with the VisualVM from 1.8.0_20
3. CPU profiler works as expected
4. compile and start the program with 1.8.0_20
5. connect with the VisualVM from 1.8.0_20
6. run CPU profiler

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
a working CPU profiler
ACTUAL -
VisualVM provides the error "Redefinition failed with error 62", the program outputs a profiler error and creates a lot of *.class files in its working directory.

ERROR MESSAGES/STACK TRACES THAT OCCUR :
objc[14452]: Class JavaLaunchHelper is implemented in both /Users/daniel/Stuff/Work/Programs/jdk1.8.0u20/bin/java and /Users/daniel/Stuff/Work/Programs/jdk1.8.0u20/jre/lib/libinstrument.dylib. One of the two will be used. Which one is undefined.
Profiler Agent: JNI OnLoad Initializing...
Profiler Agent: JNI OnLoad Initialized successfully
Profiler Agent: Waiting for connection on port 5140 (Protocol version: 14)
Profiler Agent: Established connection with the tool
Profiler Agent: Local accelerated session
Profiler Agent Error: Redefinition failed for classes:
java.lang.ApplicationShutdownHooks$1
sun.nio.ch.FileChannelImpl$Unmapper
sun.rmi.transport.DGCAckHandler$1
java.util.logging.LogManager$Cleaner
java.util.concurrent.FutureTask
sun.rmi.transport.DGCImpl$1
de.mmis.core.prototype.Prototype
com.sun.jmx.remote.internal.ServerCommunicatorAdmin$Timeout
java.util.concurrent.ThreadPoolExecutor$Worker
java.io.DeleteOnExitHook$1
java.lang.ref.Reference$ReferenceHandler
sun.rmi.transport.tcp.TCPTransport$ConnectionHandler
java.lang.UNIXProcess$4
sun.rmi.transport.tcp.TCPTransport$AcceptLoop
java.lang.ref.Finalizer$FinalizerThread
java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask
java.lang.reflect.Method
Profiler Agent Error: with message: Redefinition failed with error 62
Check JVMTI documentation for this error code.
Debug: writing class file: java.lang.ApplicationShutdownHooks$1, into file: java.lang.ApplicationShutdownHooks$1.class
Debug: writing class file: sun.nio.ch.FileChannelImpl$Unmapper, into file: sun.nio.ch.FileChannelImpl$Unmapper.class
Debug: writing class file: sun.rmi.transport.DGCAckHandler$1, into file: sun.rmi.transport.DGCAckHandler$1.class
Debug: writing class file: java.util.logging.LogManager$Cleaner, into file: java.util.logging.LogManager$Cleaner.class
Debug: writing class file: java.util.concurrent.FutureTask, into file: java.util.concurrent.FutureTask.class
Debug: writing class file: sun.rmi.transport.DGCImpl$1, into file: sun.rmi.transport.DGCImpl$1.class
Debug: writing class file: de.mmis.core.prototype.Prototype, into file: de.mmis.core.prototype.Prototype.class
Debug: writing class file: com.sun.jmx.remote.internal.ServerCommunicatorAdmin$Timeout, into file: com.sun.jmx.remote.internal.ServerCommunicatorAdmin$Timeout.class
Debug: writing class file: java.util.concurrent.ThreadPoolExecutor$Worker, into file: java.util.concurrent.ThreadPoolExecutor$Worker.class
Debug: writing class file: java.io.DeleteOnExitHook$1, into file: java.io.DeleteOnExitHook$1.class
Debug: writing class file: java.lang.ref.Reference$ReferenceHandler, into file: java.lang.ref.Reference$ReferenceHandler.class
Debug: writing class file: sun.rmi.transport.tcp.TCPTransport$ConnectionHandler, into file: sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.class
Debug: writing class file: java.lang.UNIXProcess$4, into file: java.lang.UNIXProcess$4.class
Debug: writing class file: sun.rmi.transport.tcp.TCPTransport$AcceptLoop, into file: sun.rmi.transport.tcp.TCPTransport$AcceptLoop.class
Debug: writing class file: java.lang.ref.Finalizer$FinalizerThread, into file: java.lang.ref.Finalizer$FinalizerThread.class
Debug: writing class file: java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask, into file: java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.class
Debug: writing class file: java.lang.reflect.Method, into file: java.lang.reflect.Method.class

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
package de.mmis.core.prototype;

import java.io.IOException;

public class Prototype {

public static void main(String[] args) throws IOException {
System.in.read();
System.out.println("hello world");
}

}
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
use old Java version 1.8.0_05 for profiling