I found a java code and want to use it in my project. It contains these imports that my JDK does not have :
import com.sun.awt.AWTUtilities;
import com.sun.jna.Native;
import com.sun.jna.platform.WindowUtils;
I referred to sun site and found this download page :
http://www.oracle.com/technetwork/java/javase/downloads/index.html
Is it necessary to download all JDK and JRE and replace it from SUN website? My JDK is version 6 and is up to date.
Thank you all
JNA is an additional library and not part of the standard api, you have to download it (here) and include it in your classpath.
The AWTUtilities class is only distributed with the sun jvm as an implementation detail of the api and as such subject to change, this can break any program depending on it (if possible don't use it).
WindowUtils can be found in the platform.jar, you it can find it on the same page as jna.
Your JDK should have com.sun.awt.AWTUtilities. It is in rt.jar.
Maybe the problem (for that file) is that your IDE excludes the parent the build path ... on the grounds that it is a bad idea to use those classes directly.
The com.sun.jna classes are not in rt.jar. They apparently may be found in a jna.jar, though I haven't yet found a good place to download it from. (If you use Maven, try this.)
You should not use any com.sun packages except as a last resort. These are considered to be implementation details, and they are not part of the JDK API. They can change arbitrarily between versions, so they can cause problems when you try to upgrade JDK versions.
The com.sun classes are almost always wrapped by "official" classes - you should use those instead. You can use these in a last resort situation, but they are already part of the JDK download, so there should be no extra downloading necessary.
EDIT: Looks like you're right, you do need to download some extra jars. The JNA jar is available on maven central (http://mvnrepository.com/artifact/com.sun.jna/jna/3.0.9). Especially if this is a code snippet you found, I would highly advise against using com.sun packages directly.
Related
According to the ASM FAQ, to get example ASM code, I should use the ASMifier class, like this:
java -classpath "asm.jar;asm-util.jar" org.objectweb.asm.util.ASMifier org/domain/package/YourClass.class
But that gets me the error:
Error: Could not find or load main class org.objectweb.asm.util.ASMifier
Looking at JAR files, the ASMifier class seems to be missing, though its helper classes are present:
./org/objectweb/asm/util/ASMifierClassVisitor.class
./org/objectweb/asm/util/ASMifierAnnotationVisitor.class
./org/objectweb/asm/util/ASMifierMethodVisitor.class
./org/objectweb/asm/util/ASMifierAbstractVisitor.class
./org/objectweb/asm/util/ASMifierFieldVisitor.class
This is with ASM 3.3.1, as provided by Fedora 20. Is the FAQ for a newer version, and I should be using different instructions? Did Fedora mess up the packaging (even though their bug-tracker shows nothing)? Something else?
When browsing the SVN repository of ASM, you can read up the revision history of the ASMifier: It was formerly known as the ASMifierClassVisitor which was also this utility's name in version 3.1.1.
ASM never had a reputation of maintaining binary or even compilation compatibility. Thus, you might encounter several problems like the one you describe when using non-bleeding edge versions of the library. (The authors promised to improve this after ASM's version four.) You, or the libraries that you use, should however always repackage ASM into a different namespace in order to avoid such issues. This is even recommended in the FAQ to using ASM.
For running your example, you would have to use:
java -classpath "asm.jar;asm-util.jar" \
org.objectweb.asm.util.ASMifierClassVisitor \
org/domain/package/YourClass.class
classpath:.;%JAVA_HOME%\lib\dt.jar;%JAVA_HOME%\lib\tools.jar;
I found the dt.jar and tools.jar is not the Java core class foundation. Where is the Java core class foundation?
Like this
import java.util.Date;
public class Test {}
When I compile this java file, where does it go to find the java.util.Date?
tools.jar will only be supplied with a JDK (not a JRE). I'd never heard of dt.jar before today, but a quick check suggests it is also an archive that is exclusive to the JDK.
JAVA_HOME will typically point to a JRE, not a JDK.
In general, I find it much easier to use a build tool for these types of things. I use Ant.
Now that I notice your edit. There should be no cause to add anything to the class-path in order to compile code that uses core J2SE APIs. java.util.Date is part of the J2SE.
But specifically to answer your question. It is located in the rt.jar of the JRE.
The Java core runtime classes are found in "rt.jar" if you are using a Oracle / Sun Java SE release.
If that doesn't answer your question, you need to explain what you mean by "the java core class foundation", and / or tell us the names of the classes that you can't find.
Where can I find the source code for the Java library classes? I mean classes in rt.jar.
Platform: Windows.
For old versions of Java with separate JRE and JDK downloads, download the JDK. The sources for the public classes are in src.zip.
Here's the browsable source code for OpenJDK 7.
Update: As of June 2018 grepcode seems to be down. Here you can find an alternative.
Update^2: As of October 2020, the two previous links do not work. View it at OpenJDK and vote up the answer by Nosrep, which I got it from.
Sources are in src.zip located in the installation folder:
On Windows, the JDK includes src.zip by default if I remember well.
On a Linux distro, you may have to install the sun-java6-source package.
On Mac, you'll have to download the Developer Documentation. Have a look at this answer.
If you only need to have a look at the source/implemenation, i would suggest using
Docjar
Edit
GrepCode is even better
GrepCode
You can directly browse the code online here for Java : https://zgrepcode.com/java/openjdk/10.0.2/
It is a great tool also for browsing most of the open source projects as it gives you internal linking to classes.
As almost all the suggestions seem to be either grepcode or zgrepcode which are both down, I found one from OpenJDK here: http://hg.openjdk.java.net/jdk8/jdk8/jdk/file/tip/src/share/classes/
Edit: a more complete version of all OpenJDK projects and JDK 6-15 can be found here: https://hg.openjdk.java.net/
As mention above, most of the source files can be found by downloading the SDK.
However for some classes you can find the source code (javax.ssl etc') for I suggest adding the jad eclipse plugin that will decompile any class without using external site such as Docjar.
Jad eclipse info:
http://jadclipse.sourceforge.net/wiki/index.php/Main_Page
There is also grepcode.com (not sure how old this site is, perhaps this answer is an update for new solutions now), sample query:
http://grepcode.com/search?query=java.lang.Math.sin&start=0&entity=type&n=
I have a code written in java. when i load it in eclipse it shows an error in the java code import line " The import com.sun.java.browser.plugin2 cannot be resolved"
import com.sun.java.browser.plugin2.*;
How can i fix this error..??
It's possible that it's to do with the version of Java you're building your project with, since the new applet class files were only introduced in Java 1.6 / 6.0. So, right click on your project on the left, go to Properties, Java Build Path, Libraries tab, and scroll down the list until you see JRE System Library. Note the version. If it reads less than 6.0 / 1.6, you're using an old version.
Click on JRE System Library, click Remove (make sure you have at least Java 1.6 installed!) then click Add Library. Select JRE System Library and select your Java version. If this isn't listed, go to Window > Preferences, Java > Installed JREs, click Add, and locate your JRE. Then repeat the same process and it should work.
(Edit: ignore what I said, the com.sun.* classes are hidden from the user. I don't think you can use it)
As far as I know, packages com.sun.* are implementation details of certain jvm and must not be used by application developers. They can be slightly different even between minor versions of jvm. Difference between major versions or jvms of different vendors can be sufficient. So IBM's and Sun's jvms have different structure of those packages. Only packages java.* and javax.* and org.* should be used. To fix this error correctly you must not use this package. To hack it around, you can try configure eclipse to use appropriate jvm though I don't know how to do it.
Update:
There's a FAQ entry about those packages. Thanks to R. Bemrose.
Did you type this in? Then the build path in incorrect. If not no sure what is going on.
Are you sure you are using the right JRE for your project? Like Java6?
See also JRE settings, and then make sure your project uses a Java6 JRE.
You have to add the plugin to the MANIFEST.MF dependency entry
Open MANIFEST.MF
Got to tab Dependencies
Add the plugin your referenced class is placed
You also have to be sure, that the package, the called class is lying, is added in the "Runtime" tab of the MANIFEST file.
EDIT:
The MANIFEST file you can find in the /META-INF directory
Where can I download the JSSE and JCE source code for the latest release of Java? The source build available at https://jdk6.dev.java.net/ does not include the javax.crypto (JCE) packages nor the com.sun.net.ssl.internal (JSSE) packages.
Not being able to debug these classes makes solving SSL issues incredibly difficult.
there: openjdk javax.net in the security group
src/share/classes/javax/net
src/share/classes/com/sun/net/ssl
src/share/classes/sun/security/ssl
src/share/classes/sun/net/www/protocol/https
also on this page:
src/share/classes/javax/crypto
src/share/classes/com/sun/crypto/provider
src/share/classes/sun/security/pkcs11
src/share/classes/sun/security/mscapi
These directories contain the core
cryptography framework and three
providers (SunJCE, SunPKCS11,
SunMSCAPI). SunJCE contains Java
implementations of many popular
algorithms, and the latter two
libraries allow calls made through the
standard Java cryptography APIs to be
routed into their respective native
libraries.
I downloaded the src jar from: http://download.java.net/jdk6/source/
NOTE:
This is a self extracting jar, so just linking to it won't work.
... and jar -xvf <filename> won't work either.
You need to: java -jar <filename>
cheers,
jer
if you just want read the source code:
http://grepcode.com/file/repository.grepcode.com/java/root/jdk/openjdk/6-b14/sun/security/ssl/SSLSocketImpl.java
While this doesn't directly answer your question, using the javax.net.debug system property has helped me sort through SSL issues. -Djavax.net.debug=all pretty much gives you everything in gory detail. Documentation on this is at JSSE Debugging Utilities.
One note: I've seen that on Java 1.4 and maybe 1.5 levels, the output with option "all" is not as complete as it is using the same option on the Java 1.6 level. E.g., 1.6 shows the actual contents of network (socket) reads and writes. Maybe some levels of 1.4 and 1.5 do as well, but 1.6 was more consistent.
For some unknown reason Orcale doesn't released source.jar and javadocs jar for JSE.
I found only one place where you can find them http://jdk7src.sourceforge.net/ but it's outdated and unofficial.
The only one way is to clone OpenJDK repository
Put Jad on your system path. Install JadClipse plugin for Eclipse. Use the force, read the decompiled source. :-)