ClassNotFoundException when reading object

Question

I'm trying to read a scala object(the type is Seq[(Seq[DenseMatrix[Double]], DenseMatrix[Double])] ) from a file, I have the classes in my classpath, but I still get a mysterious ClassNotFoundException. DenseMatrix is specialized for Double, could that be the problem?

Here is the stack trace:

java.lang.ClassNotFoundException: breeze.linalg.DenseMatrix
at java.net.URLClassLoader$1.run(URLClassLoader.java:217)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
at java.lang.ClassLoader.loadClass(ClassLoader.java:321)
at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:264)
at java.io.ObjectInputStream.resolveClass(ObjectInputStream.java:621)
at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1592)
at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1513)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1749)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1346)
at java.io.ObjectInputStream.readArray(ObjectInputStream.java:1684)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1340)
at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1963)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1887)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1770)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1346)
at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1963)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1887)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1770)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1346)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:368)
at scala.collection.immutable.$colon$colon.readObject(List.scala:435)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:616)
at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:988)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1865)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1770)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1346)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:368)
    at .<init>(<console>:39)
at .<clinit>(<console>)
at $anonfun$1.apply(<console>:11)
at $anonfun$1.apply(<console>:10)
at scala.tools.nsc.symtab.SymbolTable.atPhase(SymbolTable.scala:95)
at scala.tools.nsc.interpreter.Phased$class.atCurrent(Phased.scala:72)
at scala.tools.nsc.interpreter.Power$$anon$2.atCurrent(Power.scala:391)
at .<init>(<console>:10)
at .<clinit>(<console>)
at $print(<console>)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:616)
at scala.tools.nsc.interpreter.IMain$ReadEvalPrint.call(IMain.scala:704)
at scala.tools.nsc.interpreter.IMain$Request.loadAndRun(IMain.scala:914)
at scala.tools.nsc.interpreter.IMain.loadAndRunReq$1(IMain.scala:546)
at scala.tools.nsc.interpreter.IMain.interpret(IMain.scala:577)
at scala.tools.nsc.interpreter.IMain.interpret(IMain.scala:543)
at scala.tools.nsc.interpreter.ILoop.reallyInterpret$1(ILoop.scala:694)
at scala.tools.nsc.interpreter.ILoop.interpretStartingWith(ILoop.scala:745)
at scala.tools.nsc.interpreter.ILoop.command(ILoop.scala:651)
at scala.tools.nsc.interpreter.ILoop.processLine$1(ILoop.scala:542)
at scala.tools.nsc.interpreter.ILoop.loop(ILoop.scala:550)
at scala.tools.nsc.interpreter.ILoop.process(ILoop.scala:822)
at scala.tools.nsc.interpreter.ILoop.main(ILoop.scala:851)
at xsbt.ConsoleInterface.run(ConsoleInterface.scala:57)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:616)
at sbt.compiler.AnalyzingCompiler.call(AnalyzingCompiler.scala:73)
at sbt.compiler.AnalyzingCompiler.console(AnalyzingCompiler.scala:64)
at sbt.Console.console0$1(Console.scala:23)
at sbt.Console$$anonfun$apply$2$$anonfun$apply$1.apply$mcV$sp(Console.scala:24)
at sbt.TrapExit$.executeMain$1(TrapExit.scala:33)
at sbt.TrapExit$$anon$1.run(TrapExit.scala:42)

Answer 1

I've had the same problem. I solved it by putting the class files inside the libs folder that in the project folder and then add them to the classpath again.