Unity AndroidJNI resolves classes but not methods - java

I am trying to interface with native Android methods from C# in Unity using AndroidJNI, however I can only resolve classes, not methods.
I have also used the 'simpler variants', meaning AndroidJavaClass interface, but the error says its trying to resolve the methods from java.lang.Object, therefore I moved onto using AndroidJNI, but am stuck resolving the methods.
I have the following java method
public static String getParamsString2() {
return "asd";
}
and the following c# code trying to resolve the method id
AndroidJNI.GetStaticMethodID(activityClass, "getParamsString2", "()Ljava/lang/String;");
I have verified from the decompiler that the signature is correct, however I end up receiving the following error
java.lang.NoSuchMethodError: no static method "Lfi/matalamaki/plugin/UnityPlayerActivity;.getParamsString2()Ljava/lang/String;
When I decompile the class there actually is the class which contains the method
public static getParamsString2() { //()Ljava/lang/String;
L1 {
ldc "asd" (java.lang.String)
areturn
}
}
The class is also correct, fi/matalamaki/plugin/UnityPlayerActivity
when using the AndroidJavaClass interface with code
string referrer3 = new AndroidJavaClass("fi.matalamaki.plugin.UnityPlayerActivity").CallStatic<string>("getParamsString2", new object[0]);
I get the following error AndroidJavaException: java.lang.NoSuchMethodError: no static method with name='getParamsString2' signature='()Ljava/lang/String;' in class Ljava.lang.Object;
java.lang.NoSuchMethodError: no static method with name='getParamsString2' signature='()Ljava/lang/String;' in class Ljava.lang.Object;
which seems to indicate that its trying to resolve the method from java.lang.Object instead of my own class..
I've tried different parameter and return type combinations but no luck..
I've also verified the built APK dex by decompiling it..

Apparently it was Proguard that by minifying or by obfuscating removed the method or renamed it. I have no idea how after verifying I saw the method there, but maybe I wasn't paying enough attention, and it had its name changed or so.
After adding a proguard exclusion on my package and its fields and methods the problem is now solved.

Related

java.lang.NoSuchMethodError related with a class constructor

I have the following class signature:
public BlockstemRequester(RateLimiter throttler,
String url, List<String> payloadsToBeRequested, List<String> objRef) {
.
.
.
}
And I'm using that constructor at this following code:
threads.add(new BlockstemRequester(RateLimiter.create(1.0),
String.format("url...", apiKey),
chunks.get(index),
chunksObjRef.get(index)))
where:
RateLimiter is from import com.google.common.util.concurrent.RateLimiter
chunks is defined as val chunks:util.List[util.List[String]] = new util.Vector[util.List[String]]
chunksObjRef is defined as val chunksObjRef:util.List[util.List[String]] = new util.Vector[util.List[String]]
But, unfortunately I'm getting an error telling me that class constructor was not found or defined:
java.lang.NoSuchMethodError: BlockstemRequester.<init>(Lcom/google/common/util/concurrent/RateLimiter;Ljava/lang/String;Ljava/util/List;Ljava/util/List;)
Basically, I'm using this class defined in Scala at my java code project, and I did defined the scala class to use List from java to avoid any problem of incompatible types between the languages.
At runtime I'm getting this following types according to my debug process:
chunks is a Vector[Collections$SynchronizedRandomAccessList]
chunksObjRef is a Vector[Collections$SynchronizedRandomAccessList]
I appreciate any kind of help towards this problem. Thank you!
As per Java docs:
Thrown if an application tries to call a specified method of a class
(either static or instance), and that class no longer has a definition
of that method. Normally, this error is caught by the compiler; this
error can only occur at run time if the definition of a class has
incompatibly changed.
From you question it is not clear if you are getting this at compile time or run time but looks like you are having issue at run time. So, use a Java decompiler and check the .class of this class whether this method is present or not.
Most probable root cause of this issue is that library used at compile time have such a method but library used at runtime doesn't have it, and hence NoSuchMethodError.
Use decompiler and check .class file of the class.
Just solved the problem. So this was the scenario: I have a project X and using a library Y. So both X and Y have different definition of the class BlockstemRequester, both with different constructor signatures. I had to change that class name of my project and refactor my code. So, at runtime the constructor pointed out it was that one from my project X and not from that one defined in the library Y
I appreciate any advise if there is any way to approach this problem better than just renaming/refactoring my local classes
I think that the problem is with your 'typed' list.
If you change the signature to
public BlockstemRequester(RateLimiter throttler,
String url, List payloadsToBeRequested, List objRef)
Or
public BlockstemRequester(RateLimiter throttler,
String url, List<?> payloadsToBeRequested, List<?> objRef)
This will work.

Why can't I call a function from my custom library?

I made a library in java to make calling maps from google maps easier and faster but I can't seem to import the jar file correctly. I followed the answer I found on this page How to create my own java library(API)? but it seems I am still doing something wrong.
I named the package in the library com.googleMaps and then I exported the .jar file and then added that .jar file into my build path of another project. I then made a class, imported com.googleMaps.StaticMap; Which gave me an unused library warning. Finally inside my main method I called DisplayMaps("string"); which is a method inside of StaticMap; But it gives me an error saying the Method does not exist but the unused warning on the import went away.
Error is: The method DisplayMap(String) is undefined for the type MapTest1
Code:
import com.googleMap.StaticMap;
public class MapTest1
{
public static void main(String[] args)
{
DisplayMap("A Url Goes here"); // This is where im getting the error
}
}
You should call it with StaticMap.DisplayMap("A Url Goes here");. That's assuming it's a static method.
When calling a static method, you have to specify the class it belongs to, unless you are calling it from another method of the same class.
If it's not a static method, you have to create an instance of StaticMap before calling the method :
StaticMap map = new StaticMap();
map.DisplayMap("A Url Goes here");

java.lang.IllegalAccessError: tried to access method

I am getting an exception and I can't find the reason of it.
The exception I get is :
java.lang.IllegalAccessError: tried to access method Connected.getData(Ljava/lang/String;)Ljava/sql/ResultSet; from class B
The method is public.
public class B
{
public void myMethod()
{
Connected conn = new Connected(); // create a connected class in order to connect to The DB
ResultSet rs = null; // create a result set to get the query result
rs = conn.getData(sql); // do sql query
}
}
public class Connected
{
public ResultSet getData(String sql)
{
ResultSet rs = null;
try
{
prepareConnection();
stmt = conn.createStatement();
stmt.execute(sql);
rs = stmt.getResultSet();
}
catch (SQLException E)
{
System.out.println("Content.getData Error");
E.printStackTrace();
}
return rs;
}
i am using apache tomcat 5.5.12
and JAVA 1.6
This happens when accessing a package scoped method of a class that is in the same package but is in a different jar and classloader.
This was my source, but the link is now broken. Following is full text from google cache:
Packages (as in package access) are scoped per ClassLoader.
You state that the parent ClassLoader loads the interface and the child
ClassLoader loads the implementation. This won't work because of the
ClassLoader-specific nature of package scoping. The interface isn't visible to
the implementation class because, even though it's the same package name,
they're in different ClassLoaders.
I only skimmed the posts in this thread, but I think you've already discovered
that this will work if you declare the interface to be public. It would also
work to have both interface and implementation loaded by the same ClassLoader.
Really, if you expect arbitrary folks to implement the interface (which you
apparently do if the implementation is being loaded by a different
ClassLoader), then you should make the interface public.
The ClassLoader-scoping of package scope (which applies to accessing package
methods, variables, etc.) is similar to the general ClassLoader-scoping of
class names. For example, I can define two classes, both named com.foo.Bar,
with entirely different implementation code if I define them in separate
ClassLoaders.
Joel
You are almost certainly using a different version of the class at runtime to the one you expect. In particular, the runtime class would be different to the one you've compiled against (else this would have caused a compile-time error) - has that method ever been private? Do you have old versions of the classes/jars on your system anywhere?
As the javadocs for IllegalAccessError state,
Normally, this error is caught by the compiler; this error can only occur at run time if the definition of a class has incompatibly changed.
I'd definitely look at your classpath and check whether it holds any surprises.
This happened to me when I had a class in one jar trying to access a private method in a class from another jar. I simply changed the private method to public, recompiled and deployed, and it worked ok afterwards.
I was getting this error on a Spring Boot application where a #RestController ApplicationInfoResource had a nested class ApplicationInfo.
It seems the Spring Boot Dev Tools was using a different class loader.
The exception I was getting
2017-05-01 17:47:39.588 WARN 1516 --- [nio-8080-exec-9]
.m.m.a.ExceptionHandlerExceptionResolver : Resolved exception caused
by Handler execution:
org.springframework.web.util.NestedServletException: Handler dispatch
failed; nested exception is java.lang.IllegalAccessError: tried to
access class com.gt.web.rest.ApplicationInfo from class
com.gt.web.rest.ApplicationInfoResource$$EnhancerBySpringCGLIB$$59ce500c
Solution
I moved the nested class ApplicationInfo to a separate .java file and got rid of the problem.
If getData is protected then try making it public. The problem could exist in JAVA 1.6 and be absent in 1.5x
I got this for your problem. Illegal access error
I was getting same error because of configuration issue in intellij.
As shown in screenshot.
Main and test module was pointing to two different JDK. (Press F12 on the intellij project to open module settings)
Also all my dto's were using #lombok.Builder which I changed it to #Data.
From Android perspective:
Method not available in api version
I was getting this Issue primarily because i was using some thing that is not available/deprecated in that Android version
Wrong way:
Notification.Builder nBuilder = new Notification.Builder(mContext);
nBuilder.addAction(new Notification.Action(android.R.drawable.ic_menu_view,"PAUSE",pendingIntent));
Right way:
Notification.Builder nBuilder = new Notification.Builder(mContext);
nBuilder.addAction(android.R.drawable.ic_media_pause,"PAUSE",pendingIntent);
here Notification.Action is not available prior to API 20 and my min version was API 16
Just an addition to the solved answer:
This COULD be a problem with Android Studio's Instant Run feature, for example, if you realized you forgot to add the line of code: finish() to your activity after opening another one, and you already re-opened the activity you shouldn't have reopened (which the finish() solved), then you add finish() and Instant Run occurs, then the app will crash since the logic has been broken.
TL:DR;
This is not necessarily a code problem, just an Instant Run problem
In my case the problem was that a method was defined in some Interface A as default, while its sub-class overrode it as private. Then when the method was called, the java Runtime realized it was calling a private method.
I am still puzzled as to why the compiler didn't complain about the private override..
public interface A {
default void doStuff() {
// doing stuff
}
}
public class B {
private void doStuff() {
// do other stuff instead
}
}
public static final main(String... args) {
A someB = new B();
someB.doStuff();
}
In my case I was getting this error running my app in wildfly with the .ear deployed from eclipse. Because it was deployed from eclipse, the deployment folder did not contain an .ear file, but a folder representing it, and inside of it all the jars that would have been contained in the .ear file; like if the ear was unzipped.
So I had in on jar:
class MySuperClass {
protected void mySuperMethod {}
}
And in another jar:
class MyExtendingClass extends MySuperClass {
class MyChildrenClass {
public void doSomething{
mySuperMethod();
}
}
}
The solution for this was adding a new method to MyExtendingClass:
class MyExtendingClass extends MySuperClass {
class MyChildrenClass {
public void doSomething{
mySuperMethod();
}
}
#Override
protected void mySuperMethod() {
super.mySuperMethod();
}
}
I was getting similar exception but at class level
e.g. Caused by: java.lang.IllegalAccessError: tried to access class ....
I fixed this by making my class public.

Scala trouble accessing Java methods

So, I have something written in Java, and I want to extend it in Scala... The issue I'm running into is that Scala isn't seeing methods I need.
Here is how it's set up:
Player extends Mob, and Mob extends Entity.
I need to access a method in Player that isn't defined in Mob or Entity, but Scala doesn't think it exists even though Java does.
It can see methods defined by Mob and Entity just fine. Also, all the methods I'm talking about are non-static.
So, am I doing something wrong, or is this a limitation imposed by Scala?
Edit --
Here is the relevant code:
package test
import rsca.gs.model.Player
object Test {
def handle(p:Player): Unit = {
p.getActionSender().sendTeleBubble(0, 0, false);
}
}
Player class:
package rsca.gs.model;
// imports
public final class Player extends Mob {
// Implemented methods (not going to post them, as there are quite a few)
// Relevant code
private MiscPacketBuilder actionSender;
public MiscPacketBuilder getActionSender() {
return actionSender;
}
}
Error:
value getActionSender is not a member of rsca.gs.model.Player
I never encountered such problems, and you probably checked your configuration and everything else twice, so I would guess this is some Eclipse related build issue. You should try to build from the command line in order to see whether Scala or Eclipse is the problem.
Is it possible for you to run a test against the class just to see if you got the right one?
p.getClass.getMethods
... and if possible (may run into NPE) in order to find the source:
p.getClass.getProtectionDomain.getCodeSource.getLocation.getPath
When compiling the Scala class, do something like this:
scalac *.scala *.java
This way, Scala will look a the Java code to see what is available. If, however, the Java code is already compiled and provided as a jar file, just add it to the classpath used when compiling the Scala code.

NoClassDefFoundError

I have an issue where NoClasDefFoundError is being thrown. It puzzles me since I am using interfaces, and no class definition should be available. I have read through some posts which point to Classpath, but I don't believe that to be the issue here (although I may be wrong). I am using NetBeans 6.9.1 IDE.
I have created a sample setup to reproduce the issue. Four projects: Interfaces, Objects, Locator and Consumer. Below you will find the implementations.
At runtime consumer coplains about missing SomeObject implementation, which it should not be aware of since it is accepting interface.
Exception in thread "main"
java.lang.NoClassDefFoundError:
objects/SomeObject
What am I missing?
package interfaces;
public interface ISomeInterface { }
package objects;
import interfaces.ISomeInterface;
public class SomeObject implements ISomeInterface{ }
package locator;
import interfaces.ISomeInterface;
import objects.SomeObject;
public class Locator { public static ISomeInterface LocateImplementation() { return new SomeObject(); }}
package consumer;
import interfaces.ISomeInterface;
import locator.Locator;
public class Main { public static void main(String[] args) { ISomeInterface object = Locator.LocateImplementation(); }}
You can get a NoClassDefFoundError exception with interfaces just as you can with classes. Consider the "Class" in the name of the exception to be the .class file that is generated from compiling a class or interface, not a Java class.
This is saying that the class/interface objects.SomeObject isn't visible on your classpath. Check the location of that .class file and ensure that it's on your classpath - if you're positive it's there, give us some screen shots or something that might help to debug the problem.
Think of NoClassDefFoundError as a runtime linkage problem. JRE loaded one class (or an interface) and it references another class (or an interface), but that referenced class isn't found.
The only way this can happen if you have packaging/classpath issues such that your runtime environment doesn't reflect how things are at build time.
If you are launching this from IDE, make sure that you aren't ignoring any errors and launching anyway. Some classes will not be generated that way.
Usually I run into these problems not when a class is missing, but when there is an error in the static initializers.
Try running your code in a debugger, and set the exception breakpoint to break when any exception is thrown, whether caught or not. I bet you have an uncaught exception in the static initializer for some reason.
In the locateImplementation() method you are returning "new SomeObject()",
JVM needs to have its definition when called. I think it is missing.
You should check if your SomeObject class is in class path because -
Well the JVM will be running the below code -
ISomeInterface object = Locator.LocateImplementation();
and when it does that it will call Locator.LocateImplementation(). This code internally tries to instantiate your SomeObject class which it does not find in the classpath.
So your below understanding
It puzzles me since I am using
interfaces, and no class definition
should be available.
Is not really valid.
Any Interface must be declared inside class
public class Calbacks {
public interface IBaseFragmentInterface {
void NotifyMainActivity();
}
}

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