#303 DrJava won't recognize the Java 7 compiler (stuck on Java 6)
THE ISSUE: My system (including Terminal) uses Java 7u25, but DrJava is stuck on Java 6u43.
WHAT I'VE TRIED: I can't find a tools.jar file on my computer anywhere, so trying to change the path for that didn't help. I posted about this issue on stackexchange (no answers) a few days ago, and it has screenshots: http://stackoverflow.com/questions/18069708/i-cant-manage-to-get-drjava-to-update-to-java-se-7.
SYSTEM PROPERTIES: I'm running a Mac, with OS X (10.7.5) installed.
DrJava Version : drjava-20120818-r5686
DrJava Build Time: 20120818-0422
DrJava Configuration File: /Users/chrismiddleton/.drjava
Java System Properties:
apple.awt.graphics.UseOpenGL false
apple.awt.graphics.UseQuartz false
apple.laf.useScreenMenuBar true
awt.nativeDoubleBuffering true
awt.toolkit apple.awt.CToolkit
drjava.debug.port 49604
file.encoding MacRoman
file.encoding.pkg sun.io
file.separator /
ftp.nonProxyHosts local|.local|169.254/16|.169.254/16
gopherProxySet false
http.nonProxyHosts local|.local|169.254/16|.169.254/16
java.awt.graphicsenv apple.awt.CGraphicsEnvironment
java.awt.printerjob apple.awt.CPrinterJob
java.class.path /Applications/DrJava.app/Contents/Resources/Java/drjava.jar
java.class.version 50.0
java.endorsed.dirs /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home/lib/endorsed
java.ext.dirs /Library/Java/Extensions:/System/Library/Java/Extensions:/System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home/lib/ext
java.home /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home
java.io.tmpdir /var/folders/4c/82dqzw0x67qfh8dvjl5xt0140000gn/T/
java.library.path /Applications/DrJava.app/Contents/Resources/Java:/System/Library/PrivateFrameworks/JavaApplicationLauncher.framework/Resources:.:/Library/Java/Extensions:/System/Library/Java/Extensions:/usr/lib/java
java.rmi.server.hostname 127.0.0.1
java.runtime.name Java(TM) SE Runtime Environment
java.runtime.version 1.6.0_43-b01-447-11M4203
java.specification.name Java Platform API Specification
java.specification.vendor Sun Microsystems Inc.
java.specification.version 1.6
java.vendor Apple Inc.
java.vendor.url http://www.apple.com/
java.vendor.url.bug http://bugreport.apple.com/
java.version 1.6.0_43
java.vm.info mixed mode
java.vm.name Java HotSpot(TM) 64-Bit Server VM
java.vm.specification.name Java Virtual Machine Specification
java.vm.specification.vendor Sun Microsystems Inc.
java.vm.specification.version 1.0
java.vm.vendor Apple Inc.
java.vm.version 20.14-b01-447
line.separator
mrj.build 11M4203
mrj.version 1070.1.6.0_43-447
os.arch x86_64
os.name Mac OS X
os.version 10.7.5
path.separator :
socksNonProxyHosts local|.local|169.254/16|.169.254/16
sun.arch.data.model 64
sun.awt.exception.handler apple.awt.CToolkit$EventQueueExceptionHandler
sun.boot.class.path /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Classes/jsfd.jar:/System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Classes/classes.jar:/System/Library/Frameworks/JavaVM.framework/Frameworks/JavaRuntimeSupport.framework/Resources/Java/JavaRuntimeSupport.jar:/System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Classes/ui.jar:/System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Classes/laf.jar:/System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Classes/sunrsasign.jar:/System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Classes/jsse.jar:/System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Classes/jce.jar:/System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Classes/charsets.jar
sun.boot.library.path /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Libraries
sun.cpu.endian little
sun.cpu.isalist
sun.io.unicode.encoding UnicodeLittle
sun.java.command edu.rice.cs.drjava.DrJavaRoot
sun.java.launcher SUN_STANDARD
sun.jnu.encoding MacRoman
sun.management.compiler HotSpot 64-Bit Tiered Compilers
sun.os.patch.level unknown
user.country US
user.dir /Applications
user.home /Users/chrismiddleton
user.language en
user.name chrismiddleton
user.timezone America/New_York
Hi Chris,
What version of DrJava are you using? Only the latest stable release
(drjava-stable-20120818-r5686), which you can download from drjava.org, recognizes the Java 7 compiler.
DrJava invokes Java compilers programmatically (by executing a method call)
and it only recognizes compilers that it can confirm are compatible with
the version of Java that is executing the DrJava IDE. Versions of DrJava
prior to the latest stable release were released before Java 7 and will not
load the Java 7 compiler either because they do not find it or if they do
find it and determine that it is not compatible with the latest Java
release that existed at the time that version of DrJava was released.
DrJava loads and executes the classes that are compiled from DrJava (as
well as extant class files). This process will fail (generating an error
message) for class files that are compiled by a newer version of Java than
the executing JVM. Java is backward compatible (legacy class files
generally work on newer JVMs) but not the opposite. Newer version class
files have been compiled on the basis of a newer (expanded) version of the
Java core libraries, which is not available in the executing JVM (wihch has
an older version of the core libraries built-in).
If your version of DrJava is up-to-date, then I am stumped and I will have
find a former DrJava developer with a Mac who is willing to help. I
stopped using Macs several years ago when Apple abandoned support of Java
on 32 bit Macs. (After several years, support resumed, presumably through
Oracle who now develops the Mac JDK distributions, but it was too late to
persuade to go back to using Macs.)
Best,
Robert "Corky" Cartwright
Hi Chris,
I just read your support request more carefully and noticed that you in fact documented that you are using the latest version of DrJava. I am mystified but I have not run DrJava on a Mac in several years. I will try to borrow a Mac at the office tomorrow to see if I can reproduce your problem. I did try running the latest DrJava stable release on Linux using a prerelease Java 8. It worked perfectly except that DrJava mislabeled the Java 8 compiler as a Java 7 compiler.
What I would try if I were you is downloading the latest stable drjava.jar file, which is the form of the distribution that we use on Linux. You can execute this file from the command line (terminal) simply by changing the working directory to the directory containing the jar file and typing
java -jar drjava-stable-20120818-r5686.jar
You can save yourself a bit of typing by renaming
drjava-stable-20120818-r5686.jar as drjava.jar
Best,
Corky
I'm having exactly the same problem, as far as I can tell. (On a Mac, naturally.) I tried running DrJava from the command line, and it made no difference. (There was a slight irregularity in the way it asked whether to allow internet connections, but I doubt this had any impact on its choice of compiler.)
Oddly, it's aware of at least one item from JDK 7. The compiler-ready message is
ready: JDK 6.0_37 from
/Library/Java/JavaVirtualMachines/jdk1.7.0_11.jdk/Contents/Home/lib/tools.jar.
A wild guess is that somewhere in the jar file is a .class file compiled using Jave 6, and DrJava is afraid it might call something compiled using a later version of the compiler.
-- Drew McDermott
Yale CS Department
Hi Chris and Drew,
I apologize for taking so long to respond to your request. I had to borrow a MacBook from a friend and use it to track down the bug. In contrast to the Java culture which eschews gratuitous changes that break legacy Java applications, Oracle has made many changes in the organization of their Java distributions for the Mac compared to the organization that Apple used while Apple was explicitly supporting Java. In particular, Oracle appends the suffix ".jdk" to the root directory for their Mac OS Java JDK distributions. The DrJava code that determines the version of a compiler from a distribution's root directory name broke as a result of this change. I have attached a patched version of DrJava that works (at least on simple examples) on the borrowed Mac (running Mac OS X 10.7.5) that I am using. This version is a jar file rather than a packaged Mac App (which I will create shortly as part of a new DrJava stable release assuming that this patch works for you). To run this jar file, download it your Desktop (it should save under the name "drjava.jar"), open the Terminal (an app in the Utilities folder inside the Applications folder), and type the following two commands in the terminal
cd Desktop
java -jar drjava.jar
and the invoked DrJava program should display a DrJava frame with your Java 7 compiler as the compiler selected by default (it should also find an Eclipse Java 6 compiler bundled inside the drjava.jar file and perhaps a Java 6 compiler if you have a Java 6 JDK installed on your Mac).
Let me know if the attached drjava.jar file works for you.
Best,
Corky
Thanks for taking a look at the Mac/Java-7 bug report. Unfortunately,
something bogus happened with your attempt to attach the jar file. In
Thunderbird, there is a line that says there's an attachment, but
there's no actual attachment. Can you try resending just the jar
file?
I am trying again to send the attachment using SourceForge. Let's see what happens. Unfortunately, I cannot guarantee that this file is identical to the one I tested on the borrowed MacBook. I left that MacBook (containing the tested drjava.jar file) in my office at Halmstad University. I reconstructed what I think is the same jar file on my regular laptop (running Linux) that I brought home with me. I will test to see if the two jar files are identical (at least equivalent) tomorrow. in the meantime, I am uploading the reconstruction.
Hi Drew et al,
I attached the file using the attach mechanism provided by sourceforge
which I have not tested. Let me try again. Alternatively, if you send me (
corky.cartwright@gmail.com) a direct email address, I will send the
attachment to your address.
Best,
Corky
On Thu, Aug 29, 2013 at 7:41 PM, Drew McDermott airfoyle@users.sf.netwrote:
Related
Support Requests:
#303Sorry; I didn't realize I had to go to your web-based bug-report
system to find the jar file.
I downloaded it, and it now finds Java 7. Thanks a lot.
Beware that if you currently can run the DrJava Mac OS X App with Java 7 that the Oracle Java 7 JDK is reportedly incompatible with the Apple Jar Launcher used in the DrJava app. For reasons I do not understand, the DrJava app worked with Java 7 before I installed a recent Java update from Apple.
After I updated the Apple Java 6 JDK to the latest release (6.0_51), the DrJava app no longer loads the Oracle Java 7 compiler because the Apple Jar launcher used by the DrJava app does not recognize the Oracle Java 7 JDK. If you inspect "System Properties" in such a scenario, it shows that DrJava is being executed by Apple's Java 6 JVM not Oracle's Java 7 JVM. A Java 6 JVM will not load Java 7 class files including those for a Java 7 compiler. If the Oracle Java 7 JDK is installed, DrJava typically finds the Java 7 compiler but rejects it because it cannot be loaded. The jar launchers from Apple and Oracle appear completely incompatible with one another. If we subsequently bundle DrJava with the Oracle jar launcher, such an app will not work on systems where the Oracle Java 7 JDK has not been installed.
If you want to run DrJava using an Oracle Java 7 JDK for Mac OS X and the corresponding Java 7 compiler, you should download the DrJava jar release and run DrJava from a terminal command line using the command
drjava -jar drjava-stable-20130901-r5756.jar
In the future, we may create a DrJava app for Mac OS X that uses the Oracle jar launcher but such an app will only work for Macs with Java 7 installed; it will not work with an Apple Java 6 JDK. Since we do not want to create two different Mac OS X apps for DrJava, we do not anticipate making this change until Java 8 is officially released, making Java 6 obsolescent.