FULL PRODUCT VERSION :
java version "1.9.0-ea"
Java(TM) SE Runtime Environment (build 1.9.0-ea-b68)
Java HotSpot(TM) 64-Bit Server VM (build 1.9.0-ea-b68, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 6.1.7601]

A DESCRIPTION OF THE PROBLEM :
with classpath with double quotes as an environment in windows commandline environment, javac fails.

When using java8 or java9 with classpath as a parameter it works

When not using double quotes it works

REGRESSION. Last worked in version 8u5

ADDITIONAL REGRESSION INFORMATION:
javac full version "1.9.0-ea-b68" --> fails
javac full version "1.8.0_05-b13" --> works
javac full version "1.6.0_37-b06" --> works


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
javac -cp . X9.java
jar -cvf X9.jar X9.class
set CLASSPATH="X9.jar;."
javac J9.java

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
no error
ACTUAL -
javac return InvalidPathException

ERROR MESSAGES/STACK TRACES THAT OCCUR :
An exception has occurred in the compiler (1.9.0-ea). Please file a bug at the Java Bug Database (http://bugreport.java.com/bugreport/) after checking the database for duplicates. Include your program and the following diagnostic in your report. Thank you.
java.nio.file.InvalidPathException: Illegal char <"> at index 0: "X9.jar
        at sun.nio.fs.WindowsPathParser.normalize(WindowsPathParser.java:182)
        at sun.nio.fs.WindowsPathParser.parse(WindowsPathParser.java:153)
        at sun.nio.fs.WindowsPathParser.parse(WindowsPathParser.java:77)
        at sun.nio.fs.WindowsPath.parse(WindowsPath.java:94)
        at sun.nio.fs.WindowsFileSystem.getPath(WindowsFileSystem.java:255)
        at java.nio.file.Paths.get(Paths.java:84)
        at com.sun.tools.javac.file.Locations.getPathEntries(Locations.java:156)
        at com.sun.tools.javac.file.Locations.access$300(Locations.java:88)
        at com.sun.tools.javac.file.Locations$SearchPath.addFiles(Locations.java:225)
        at com.sun.tools.javac.file.Locations$SearchPath.addFiles(Locations.java:231)
        at com.sun.tools.javac.file.Locations$ClassPathLocationHandler.computePath(Locations.java:501)
        at com.sun.tools.javac.file.Locations$SimpleLocationHandler.setLocation(Locations.java:448)
        at com.sun.tools.javac.file.Locations$ClassPathLocationHandler.lazy(Locations.java:513)
        at com.sun.tools.javac.file.Locations$ClassPathLocationHandler.getLocation(Locations.java:477)
        at com.sun.tools.javac.file.Locations.getLocation(Locations.java:749)
        at com.sun.tools.javac.file.JavacFileManager.getLocation(JavacFileManager.java:917)
        at com.sun.tools.javac.file.JavacFileManager.getClassLoader(JavacFileManager.java:643)
        at com.sun.tools.javac.processing.JavacProcessingEnvironment.initProcessorClassLoader(JavacProcessingEnvironment.java:236)
        at com.sun.tools.javac.processing.JavacProcessingEnvironment.<init>(JavacProcessingEnvironment.java:210)
        at com.sun.tools.javac.processing.JavacProcessingEnvironment.instance(JavacProcessingEnvironment.java:170)
        at com.sun.tools.javac.main.JavaCompiler.initProcessAnnotations(JavaCompiler.java:1018)
        at com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:829)
        at com.sun.tools.javac.main.Main.compile(Main.java:253)
        at com.sun.tools.javac.main.Main.compile(Main.java:141)
        at com.sun.tools.javac.Main.compile(Main.java:56)
        at com.sun.tools.javac.Main.main(Main.java:42)

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
J9.java:
public class J9 {
  public static void main(String argv[])
  {
    System.out.println("Hello world");
  }
}

X9.java:
public class X9 {}
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
javac -classpath %CLASSPATH% J9.java