Imported jar files creates empty packages - java

I am importing a Jar file "com.ibm.mq.jar" into my workspace(Eclipse IDE).
While importing, a screen came where I could see all the classes in the Jar file.
After I imported it into the work space, I was able to import the package and following statement didn't give any error.
import com.ibm.mq.*;
But, in code I am not able to use any of the classes which were there in the package.
Like, "MQC" is a class in the package, but in code it doesn't reflect("MQC cannot be resolved as a type" error comes if I try to use it).
This jar file actually contains Websphere MQ API classes.
Can anyone advise, what am I missing.

If you're using MQ 7, check its documentation here. There was some stuff going on about deprecation of com.ibm.mq.mqc and, depending on the version you use, that class was replaced by com.ibm.mq.constants.MQConstants. Like this one, there are other cases.
In fact com.ibm.mq only contains the exception MQException, so you won't find any classes there. I suggest you check the version you're using and dig a little deeper into the docs, as a first step.

Related

Eclipse error: “The import ... cannot be resolved”

I know I am asking the very popular question. But I can not find the solution to the problem. I have a sandbox to which I added a code of the unit test MulticurveBuildingDiscountingDiscountAUDTest.java file and commented it.
Then I added the main method and I could successfully run the program (print something in a console).
Finally, I uncommented the code of the MulticurveBuildingDiscountingDiscountAUDTest.java file and I saw the following error:
The import com.opengamma.analytics.financial.instrument.index.GeneratorSwapFixedONMaster cannot be resolved.
And further in the code:
GeneratorSwapFixedONMaster cannot be resolved
I know that this import is located in the og-analytics src/test/java location, which I believe is not listed anywhere in the build path. I believe the problem is with a build path options and specially with classes like GeneratorSwapFixedONMaster which were created specially for tests. I have been playing around with cleaning, rebuilding projects, reinstalling and as a result updating the JRE. I have visited these Import *** cannot be resolved [duplicate] and these Eclipse error: “The import XXX cannot be resolved” questions.
Do you know what shall I do to cure the following error?
I have many problems with other imports from the original MulticurveBuildingDiscountingDiscountAUDTest.java file as well.
Update: #1 is a location of my file. #2 is the location of classes this project uses. The MulticurveBuildingDiscountingDiscountAUDTest.java file is taken from the src/test/java
Update 2: one may see that in Libraries I have included all the dependencies I might need (at least I do not know what else to add). The Maven Dependencies contains the hole og-analytics package:
You included the source (src) folder og-analytics/src/main/java which contains the *.java files instead of the classes (bin or classes) folder with the *.class files (in your case, probably og-analytics/target/classes).
But instead using Add Class Folder... you should add the project og-analytics in the tab Projects. Or even better, in the Maven pom.xml file add the dependency to the project og-analytics like you did for og-util.
I know that this import is located in the og-analytics src/test/java location, which I believe is not listed anywhere in the build path.
Perfectly explains your problem. In order to import any class, you must either have the source in your build path, or some directory that contains a compiled version of that class. It is that simply.
The answer is: get clear on your project setup. If you intend to use classes from somewhere, you have to make them available somehow. Otherwise it will not work. In your case: if your tests want to make use a certain thing - then you should probably add that "thing" to your test project (you should avoid putting test-only stuff to your "product" projects).
That is all there is to this.

Jars with default package

I found this question -> Import custom libraries in Java
And #Andy Thomas-Cramer said that the classes in "stdlib.jar" from "An introduction to programming in Java" have no packages, so they are in the default package.
Isn't this a bad practice? If you have something with no package the IDEs' auto-completion is quite slower. And also this means that we could not use any of the classes, in that jar, from classes with packages different then the default?
Can someone please tell me how we could deal with this?
EDIT:
I have 2 jars and I put them in Referenced libraries, they both have a bunch of classes in default package. When I create class in different package then the default - lets say org.myquestion I can't access the classes from the jars anymore.
This is something that really bugs me... First I can't create my own package and use anything from the jars. Second my IDE's (I use eclipse) auto-complete goes terrible - I guess it searches to meany classes at once... What I want to do is to put somehow the jars in some namespace... and to be able to access them like org.someones.libs.SomeClass
It certainly is bad practice to use the default package. A package groups classes and provides them with access protection (protected, package private) and functions as a unique namespace.
You can always use classes from every package, them being default or not, you can always mix.
Download the jar source code, And built it to jar by yourself and added the package name whatever your like.That's will solve your problem.
Importing classes inside JAR files that are in the default package
I ran into the exactly same problem as you did. The problem is the jar file "stdln.jar" has no named package, say, only with default package.
You cannot import a class from a default package, basically, since the import operation needs the package name:
import packagename.*;
So there are only two way to fix this problem:
the easier one: Do not create a package in your src folder and use default package two! Every class in stdln.jar would be imported to your src automatically.
Like this:
enter image description here
try to create your own jar file with a named package and copy all the class file into your newly-created jar file.
Since the stdln.jar is only used for education, so which you are gonna choose does not really matter. In real development, we never use default named package since it's not really a good practice, always leading to some confusing stuff.
Hope this would help you!

Java - how to get dependencies to ignore each other?

We are developing a fairly large project and have many dependencies. Recently, we ran into an issue with a conflict between two of them, agileAPI.jar and axis.jar. Both are 3rd party libraries.
The code in question depends directly on agileAPI.jar. If I build it with just that in the build path, everything that depends on it works correctly.
As soon as I add axis.jar to the build path (just adding it, not writing code that depends on it), everything goes wrong. Some of the code that depended on the first library is now throwing exceptions from the 2nd library. It is as if the first library is picking and choosing methods to call from the 2nd library, instead of whereever it was calling them from prior.
I have code in the project that needs axis.jar directly, so I can't just remove it from the build path. I need to find a way to have these two exist in the same build path, but ignore each other.
It should be noted that both libraries coexisted prior to a recent upgrade with agile. I have been working with Oracle's support team to try and resolve this. After two weeks, though, I am looking for other sources of help.
Our environment is Windows and Eclipse, although in testing this, it also occurs when running java from a command line. Our JDK is 1.5.0_22.
Any help would be appreciated.
Thank you,
David
EDIT:
As requested, here are the stack traces that we see. The first stack trace is printed in the code beyond my control:
java.lang.NoSuchMethodError: org.apache.axis.description.OperationDesc.setStyle(Lorg/apache/axis/constants/Style;)V
at com.agile.webfs.components.fileserver.client.FileServerSoapBindingStub._initOperationDesc1(FileServerSoapBindingStub.java:37)
at com.agile.webfs.components.fileserver.client.FileServerSoapBindingStub.<clinit>(FileServerSoapBindingStub.java:20)
at com.agile.webfs.components.fileserver.client.FileServerWSServiceLocator.getFileServer(FileServerWSServiceLocator.java:43)
at com.agile.webfs.client.IFSLocator.getRemoteFileServer(IFSLocator.java:128)
at com.agile.webfs.client.IFSLocator.getConnection(IFSLocator.java:101)
at com.agile.api.pc.EJBLookup.createFileSession(EJBLookup.java:444)
at com.agile.api.pc.EJBLookup.getFileSession(EJBLookup.java:432)
at com.agile.api.pc.attachment.IFSOutputStream.getFileSession(IFSOutputStream.java:133)
at com.agile.api.pc.attachment.IFSOutputStream.copyFrom(IFSOutputStream.java:87)
at com.agile.api.pc.attachment.IFSOutputStream.copyFrom(IFSOutputStream.java:115)
at com.agile.api.pc.TableAttachment.uploadFile(TableAttachment.java:886)
at com.agile.api.pc.TableAttachment$AddFiles2Action.doSdkAction(TableAttachment.java:724)
at com.agile.api.common.SDKAction.run(SDKAction.java:23)
at com.agile.api.common.OracleAuthenticator.doAs(OracleAuthenticator.java:131)
at com.agile.api.common.Security.doAs(Security.java:54)
at com.agile.api.common.Security.doAs(Security.java:109)
at com.agile.api.pc.TableAttachment.addFiles2(TableAttachment.java:483)
at com.agile.api.pc.TableAttachment.createNewBlob2(TableAttachment.java:459)
at com.agile.api.pc.TableAttachment.doCreateServerRowWithParam(TableAttachment.java:363)
at com.agile.api.pc.Table.createTableRow(Table.java:238)
at com.agile.api.pc.TableAttachment.createTableRow(TableAttachment.java:169)
at com.agile.api.pc.Table.createRow(Table.java:202)
at com.[snip].updateAttachments(VaultImportService.java:3068)
at com.[snip].processIncorporatedFile(VaultImportService.java:926)
at com.[snip].processPdxFile(VaultImportService.java:532)
at com.[snip].processPdxRequest(VaultImportService.java:388)
at com.[snip].<init>(VaultImportService.java:299)
at com.[snip].main(VaultImportService.java:3660)
After the exception bubbles up and we catch it, the stacktrace that we print looks like:
at com.agile.api.pc.Session.createError(Session.java:1772)
at com.agile.api.pc.EJBLookup.createFileSession(EJBLookup.java:454)
at com.agile.api.pc.EJBLookup.getFileSession(EJBLookup.java:432)
at com.agile.api.pc.attachment.IFSOutputStream.getFileSession(IFSOutputStream.java:133)
at com.agile.api.pc.attachment.IFSOutputStream.copyFrom(IFSOutputStream.java:87)
at com.agile.api.pc.attachment.IFSOutputStream.copyFrom(IFSOutputStream.java:115)
at com.agile.api.pc.TableAttachment.uploadFile(TableAttachment.java:886)
at com.agile.api.pc.TableAttachment$AddFiles2Action.doSdkAction(TableAttachment.java:724)
at com.agile.api.common.SDKAction.run(SDKAction.java:23)
at com.agile.api.common.OracleAuthenticator.doAs(OracleAuthenticator.java:131)
at com.agile.api.common.Security.doAs(Security.java:54)
at com.agile.api.common.Security.doAs(Security.java:109)
at com.agile.api.pc.TableAttachment.addFiles2(TableAttachment.java:483)
at com.agile.api.pc.TableAttachment.createNewBlob2(TableAttachment.java:459)
at com.agile.api.pc.TableAttachment.doCreateServerRowWithParam(TableAttachment.java:363)
at com.agile.api.pc.Table.createTableRow(Table.java:238)
at com.agile.api.pc.TableAttachment.createTableRow(TableAttachment.java:169)
at com.agile.api.pc.Table.createRow(Table.java:202)
at com.[snip].updateAttachments(VaultImportService.java:3068)
at com.[snip].processIncorporatedFile(VaultImportService.java:926)
at com.[snip].processPdxFile(VaultImportService.java:532)
at com.[snip].processPdxRequest(VaultImportService.java:388)
at com.[snip].<init>(VaultImportService.java:299)
at com.[snip].main(VaultImportService.java:3660)
In both cases, the line "at com.agile.api.pc.Table.createRow(Table.java:202)" is the agileAPI call that I am making. I have removed our package structure, as it identifies the company that I work for. They value privacy and security.
I'd advise you to check these two things first:
Open the axis.jar file with some zip utility, like 7-Zip or WinRar. See if there's a folder called "services" in the META-INF folder in the jar. If there is, it's possible that the axis.jar file specifies implementations for specific interfaces that somehow don't interoperate with agileAPI. Also do the same for agileAPI.jar, since it might itself declare an interface implementation that axis doesn't like.
Open both agileAPI.jar and axis.jar with a zip utility, then check if there's packages with the same name. If there's none, it won't be a naming conflict. If there's one or more, open the corresponding folders and do the same check recursively. If you end up with at least one class with the same name in the same package across the two jars, it's probably a naming conflict.
That should catch the most obvious issues. If none of this is the case, we'll need to look deeper.
A way to solve such classpath issues is to use a module system such as OSGi or the NetBeans Platform module system where each module has its own classloader.

Java app suddenly not compiling with jdev

I have been working on an inherited code base that is a Java web app and just today it stopped compiling. I am getting errors that it can't find some classes that are declared in the code.
My code base is set up like this: I've got the main package and then, for some reason, both inside it and at the same level of it, I've got a .jar that holds a supplemental package, com.oreilly.servlet to be exact. I have some files in my main code base that import com.oreilly.servlet.MultipartRequest and utill today they had no problem finding them.
I have since wiped my local version and checked out the last revision which I know compiled last timed I made any changes to the java files, leading me to believe my issue is jdeveloper.
The errors I am getting are that package com.oreilly.servlet doesn't exist and subsequently that it cannot find class MultipartRequest.
I have also broken out the jar file (which by the way is included int he Libraries and Classpath section of jdev) into a package structure to no avail.
Any help would be much appreciated.
Sounds like an opportunity to update and refactor to me. I stumbled across the com.oreilly package years ago, haven't seen it since. I say remove it from the code and upgrade to the more standard javax.servlet classes (usually found in a servlet-api.jar or something similarly named bundled with your web app server).

Eclipse 3.5+ - Annotation processor: Generated classes cannot be imported

I am using a 3rd party annotation processor for generating meta-data code (.java files) from the annotated classes in my project.
I have successfully configured the processor through Eclipse (Properties -> Java Compiler -> Annotation Processing) and the code generation works fine (code is automatically created and generated). Also, Eclipse successfully auto-completes the generated classes and their fields, without any errors. Let's say that I have a class "some.package.Foo" and that the generated meta-data class is "some.package.Foo_". By the help of auto-completion, I can get the following code in the Eclipse editor, without any errors:
import some.package.Foo_;
...
public class Test {
void test() {
Foo_.someField = null; // try to access a field from the generated class Foo_
}
}
However, as soon as I actually build the project (or just save the file since Build automatically is enabled), I get the error which tells that "some.package.Foo_" cannot be resolved.
It seems like Eclipse is generating and compiling the some.package.Foo_ at the same time, or more likely.
I found two temporary solutions (which are practically hindering the use of the annotation processor in the first place):
Before each build of that generated classes, right click on every generated file go to Properties and uncheck the "Derived" tick. After that, I do the cleanup of the project and the imports are fine - there are no more errors. However, if I do the cleanup one more time, the errors again show up, because the generation of the files causes the "Derived" tick to be checked again (automatically). So this is really annoying and time-consuming.
I also uncheck the "Derived" tick
from all those files, and this time
I uncheck the "Derived" tick from
the source folder and packages which
contain those files. Then I disable
the annotation processor, and then
do the cleanup. There are no more
import errors, even if I do another
cleanup, but there is no benefit of
using the annotation processor,
because if I was to change something
which would update the model, I need
to turn the annotation processor
back on, and repeat this tedious
procedure to turn it off, after it
has generated the new version of
those files.
Is this a bug in Eclipse? If yes, is there a better workaround or quick-fix than the two I have stated above? If not, what should I try to solve the problem?
I also tried rearranging the order of the libraries on the build path and it doesn't help.
I assume that you are generating sources in the last processor round. This is not recommended way and leads exactly to the problem that you had.
Explanation is here: http://code.google.com/p/acris/wiki/CodeGenerationPlatform_Pitfall_Rounds
So the my advise is to generate sources in regular processing rounds and final round should be used just for notification that processing is over or something like that.
Hopefully this helps you.
I have a similar problem, and the only thing I've found is that it's the imports specifically that don't work, but the references in the class itself do work. The workaround I've used is to use the FQCN in all cases where the generated class is needed (except when the generated class is in the same package, since then the import is obviously not needed).
So to use your example, I'd do:
public class Test {
void test() {
some.package.Foo_.someField = null; // try to access a field from the generated class Foo_
}
}
My only guess then is that the eclipse compiler is processing the imports before doing the annotation processing, which imho must be a bug in eclipse.
I know this question is over a year old, so I'd be interested to know if you've found any other way to fix it.
We were experiencing a similar problem and apparently just solved it, so thought of sharing it at SO, in case it helps someone.
We are using:
Eclipse Indigo (Build id: 20120216-1857)
m2e Connector for maven
openJPA for static metamodel class generation
Our problem:
Say, we have a package named com.abc.xyz and an entity class in there named OurEntity. When we build the projects (JPA, EJB, EAR etc. all together with an mvn clean at the beginning) the metamodel classes get generated. And also get appropriately packaged within the PU jar. But when we try to import the generated metamodel class com.abc.xyz.OurEntity_, Eclipse cannot resolve it. OP apparently got past this point:-). Maven build failed, saying it could not resolve that class. Not much help from google except for a few bug reports such as this one: https://bugs.eclipse.org/bugs/show_bug.cgi?id=350378
That bug report said importing the whole package as opposed to the single class helped. So, tried that, but with no benefit. It also said (and so did David Heitzman) that using the fully qualified class name worked for them. That did not work either.
The solution:
Added the PU jar to Eclipse build path for the project that needed to use the metamodel classes. All of a sudden all the red underlines went away (not a surprise). But the fear was there might be two PUs in the same ear. But maven automagically took care of that.
As this rather old question got some attention without pointing to the very probable eclipse bug the OP was specifically asking for, I'd like to complement the above answers with a pointer to the eclipse bug tracker:
Cannot resolve import for generated class IF processing annotations with parameters referencing constants
The workarounds include
doing a wildcard import of the package defining the generated classes (i.e. import some.package.*;)
using the fully qualified name of your generated class, i.e. referring to some.package.Foo in your code and not using an import
switch to a newer Eclipse. This specific eclipse bug is resolved with Eclipse version 4.4 (aka Luna).

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