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).
Related
We have maven apps that until recently were on JDK8. We just upgraded them to JDK11 and are trying to take advantage of the JPMS from JDK9 by making our utility libraries into modules.
We originally had this kind of path:
utils/some-library1/src/main/java/com/company/team/utils/lib1/Util1.java
There, java is the "source root".
So a colleague placed the module-info.java file in the lib1 folder and declared it thus:
module utils.lib1 {
exports com.company.team.utils.lib1;
}
From the command line that builds and works, so he assumes everything is all module-y goodness.
But when I opened in Intellij, it had an ugly red line and the message said I should move it to source root. It then moved it to the "java" folder above. Fair enough.
That caused me to dig around trying to find out more about this JPMS that my colleague had implemented. After a lot of searching and experiments, I also determined that the "java" folder, as "source root", should be renamed to the name of the module ("utils.lib1"). So now I have these two files:
utils/some-library1/src/main/utils.lib1/module-info.java
utils/some-library1/src/main/utils.lib1/com/company/team/utils/lib1/Util1.java
And even Intellij is happy. Hooray! So I refactor all the other libraries. Suddenly I hit a major snag in let's call it lib2 with this line:
module utils.lib2 {
exports com.company.team.utils.lib2;
requires java.ws.rs;
}
Intellij flags the module with the red error squiggle again, this time saying:
Module 'utils.lib2' reads package 'javax.activation' from both 'jakarta.activation' and 'jakarta.activation'
I did some digging and found out the following:
java.ws.rs pulls in one of the following (it depends on which app):
javax.ws.rs-api-2.1.1.jar
jakarta.ws.rs-api-2.1.6.jar
Their module-info.java files contain this line:
requires transitive java.xml.bind;
Which pulls in one of:
jakarta.xml.bind-api-2.3.2.jar
jakarta.xml.bind-api-2.3.3.jar
jaxb-api-2.4.0-b180830.0359.jar
Which all have this line:
requires transitive jakarta.activation;
And that's where I give up. Our libraries are big hefty things that are hard to parse completely, so to simplify I created a maven app with just one class and all it does is import javax.ws.rs.core.Link.
And IntelliJ still gives that crazy error that I can't figure out and Google has been adamant in refusing to tell me.
Is it really broken or is Intellij just as confused as I?
I gave the long story both to show what we've done and to let you know that I'm very new to modules. So if it's a simple thing, please excuse me. I am just stumped though.
Additionally, are there any obvious tests one can perform at the command line to validate module configuration?
I've had inconsistent luck with jdeps, javac, and actually running as indicators of problems.
My suspicion is that things only work now because they're all in the unnamed module. But I need to get everything working if I'm going to convince anyone to change it.
EDIT
This question was reported as already answered, but that is incorrect. The suggested link deals with two different packages (A & B) importing package X. But in my case, the error is that the same package (A & A) imports package X. And this is done a few transitives down, so I have no control over the imports and can't see how to do an exclusion. Also, this problem can be repeated with just single requires statement in module-info.java!
Plus, there is a second question here that is also important that has not been addressed: how to validate the module configuration from command line (without involving the IDE at all).
I also determined that the "java" folder, as "source root", should be renamed to the name of the module
No, it should not. The java source root should be left as is but you must create a package name corresponding to your module name, so it should be /src/main/java/ - source root and then utils/lib1 directory - whidh would be the package.
I came across exact same warning in Intellij and it was genuine. In my case the collision was coming from three separate dependencies using same module name (i.e. 'jakarta.activation'):
'jakarta.activation:jakarta.activation-api:1.2.2'
'javax.activation:javax.activation-api:1.2.0'
'com.sun.activation:jakarta.activation:1.2.2'
It got it resolved for my project by applying explicit exclusions on dependencies which were pulling the last two.
While setting up a project as a template for Slick2d based projects following the instructions here:Slick2d wiki using the provided code for testing setup here at run-time I keep getting a giant block of sealing errors. My thought is that this problem stems from the version of ljgwl.jar in both libraries, however Slick requires both in order to function properly. How can I resolve this?
Package sealing is a Java feature implemented in part in the JAR file format. It is discussed in several places, including in Oracle's Java Tutorial, but the bottom line is that when package sealing is enabled in a Jar's manifest, no classes belonging to that package can appear in any other JAR file.
My thought is that this problem stems from the version of ljgwl.jar in both libraries, however Slick requires both in order to function properly.
I'm not sure what you mean by "library", as that is not a Java concept. I suspect, however, that you're trying to say that you somehow have ljgwl.jar files from two separate sources, and you've put both into your project classpath. That would indeed be a problem, and more than just for package sealing. You can, in fact, be thankful for the sealing errors, for they may have saved you from subtler, more difficult to diagnose runtime errors.
How can I resolve this?
You should have only one copy of LWJGL in your classpath, regardless of any requirements enforced by package sealing, and regardless of how the classes are packaged in jar files. It looks like the Slick2D distribution may come with a copy of LWJGL -- in that case, it's probably wisest to use that one. As long as it's in your classpath (as it must be anyway for Slick2D to use it), any class anywhere in your application can use it.
It gets tricky if you need to contend with a inconsistent requirements for LWJGL version, or if you have obtained a JAR that incorporates the LWJGL classes along with something else, but that doesn't change the bottom line: you must choose one version of LWJGL, use that version exclusively within your application, and include only one copy of it in your classpath.
I had to include some bittorrent java library to my Android project. My workspace: Android Studio 1.0.2 (osx) and jdk8. I've connected its maven-repository (ttorrent:1.4) with Gradle and after starting using main classes and features i've got an error:
java.lang.NoSuchMethodError: No static method encodeHex([BZ)[C in class Lorg/apache/commons/codec/binary/Hex; or its super classes (declaration of 'org.apache.commons.codec.binary.Hex' appears in /system/framework/ext.jar).
I went to library's code and find out that it's using org.apache.commons.codec from where ttorrent is importing encodeHex and calling it. Looks like binaryHex method is gone! Or it never been. But I went to commons.codec's code and found binaryHex in its place and with arguments that I was looking for. How come? Why? My Android Studio found it. But java runtime not.
In fact, the decision was more difficult than I thought. Let's start with the fact that I came across an article by Dieser Beitrag'a, from which it is clear that not one I had similar problems. The whole thing turned out that within the Android operating system already has some libraries that have a higher priority use, rather than loaded with dependencies along with the application. Among them there and my org.apache.commons.codec.
Yes, such things.
To solve the problem in two ways, either you need to pump source code library and using some tool to rename the project (i.e. org.apache.commons.codec to org.apache.commons.codec.android), collected it to a .jar file, include .jar in a project and at code use imports of the necessary classes only "our" library, or just get the required class to your project and do not pull a megabytes of unneeded code. However, I did just that.
Thanks for help!
I have recently written a Selenium program in Java that works perfectly with the FireFoxDriver(). My step 2 is to be able to run this program on my Android device with Selendroid. I went on their website here and have been able to download the jar and connect to their localhost with port:4444.
However, when I try their example, Eclipse doesn't recognize the SelendroidDriver() and suggests me to go back to WebDriver().
Here is their code:
SelendroidCapabilities capa = new SelendroidCapabilities("io.selendroid.testapp:0.10.0");
// My error appears when I create the new SelendroidDriver().
WebDriver driver = new SelendroidDriver(capa);
WebElement inputField = driver.findElement(By.id("my_text_field"));
Assert.assertEquals("true", inputField.getAttribute("enabled"));
inputField.sendKeys("Selendroid");
Assert.assertEquals("Selendroid", inputField.getText());
driver.quit();
I have also noticed that the SelendroidDriver class does not appear in my files although I downloaded the Selendroid jar file, version 0.10.0.
For those of you who are curious about how I fixed my problem, here is what I did:
I went to this site to get the selendroid-client jar file corresponding to the standalone version I had.
Downloading the standalone jar file was somehow not enough.
I was facing the same problem till I found the SelendroidDriver class here. Import this and change the package name according to your project.
SelendroidDriver.java has classes implementing interface methods, which in Java 1.6 can be annotated with #Override. However, in Java 1.5, #override could only be applied to methods overriding a superclass method.
Go to your project preferences and set the "Java compiler level" to 1.6 and also make sure you select JRE 1.6 to execute your program from Eclipse.
After adding this class, you would still see multiple dependency errors, but now in the SelendroidDriver.java file. You can import these classes now to counter these errors. Ensure that the package hierarchies are maintained correctly, in accordance with the GitHub directories and your working project.
After importing all these classes, the constant fields SWITCH_TO_CONTEXT, GET_CONTEXT_HANDLES and GET_CURRENT_CONTEXT_HANDLE were not being resolved. I used a poor workaround of changing them to some other available constant field for testing this sample.
I struggled a lot with this error and finally came to know that the paths have been changed in the latest releases. Use these paths and it shall work:
import io.selendroid.common.SelendroidCapabilities;
import io.selendroid.client.SelendroidDriver;
Tested this for versions 0.15.0 & 0.17.0
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.