Develop Reference

Error 'java.lang.IllegalArgumentException: Plugin already initialized!' found

I'm trying to use a simple socket server to receive some commands(bukkit api).
With the thread, the plugin can receive commands and send it to the main server, so that i can control the server.
But when i tried to use a use a thread to solve the problem, an error happened:
CODE:
package tiance.auroracore;
import org.bukkit.Bukkit;
import org.bukkit.plugin.java.JavaPlugin;
import org.bukkit.scheduler.BukkitRunnable;
import tiance.auroracore.metrics.Metrics;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
public final class AuroraCore extends JavaPlugin {
private int port;// 默认服务器端口
private String AcceptCommand;
public AuroraCore() {
this.port=9028;
this.AcceptCommand=new String();
}
// 创建指定端口的服务器
public AuroraCore(int port) {//构造方法
this.port = port;//将方法参数赋值给类参数
this.AcceptCommand=new String();
}
// 提供服务
public void service() {//创建service方法
ServerSocket server;
try {
server = new ServerSocket(port);//创建 ServerSocket类
}
catch (IOException e) {
System.out.println("Error! Cannot start the server! Is the port already used?");
return;
}
while (true) {
try {// 建立服务器连接
Socket socket = server.accept();// 等待客户连接
try {
DataInputStream in = new DataInputStream(socket
.getInputStream());// 读取客户端传过来信息的DataInputStream
DataOutputStream out = new DataOutputStream(socket
.getOutputStream());// 向客户端发送信息的DataOutputStream
while (true) {
String accept = in.readUTF();// 读取来自客户端的信息
AcceptCommand = accept;
Bukkit.dispatchCommand(Bukkit.getConsoleSender(), AcceptCommand);
}
} finally {// 建立连接失败的话不会执行socket.close();
socket.close();//关闭连接
server.close();//关闭
}
} catch (IOException e) {//捕获异常
e.printStackTrace();
}
}
}
#Override
public void onEnable() {
new BukkitRunnable(){
public void run(){
new AuroraCore().service();//调用service方法
}
}.runTaskAsynchronously(this);
int pluginId = 13929;
Metrics metrics = new Metrics(this, pluginId);
saveDefaultConfig();
}
#Override
public void onDisable() {
}
}
ERROR
[12:45:28 WARN]: [AuroraCore] Plugin AuroraCore v1.0.0 generated an exception while executing task 2
java.lang.IllegalArgumentException: Plugin already initialized!
at org.bukkit.plugin.java.PluginClassLoader.initialize(PluginClassLoader.java:218) ~[craftbukkit-1.16.5.jar:3096a-Bukkit-af1a232]
at org.bukkit.plugin.java.JavaPlugin.<init>(JavaPlugin.java:52) ~[craftbukkit-1.16.5.jar:3096a-Bukkit-af1a232]
at tiance.auroracore.AuroraCore.<init>(AuroraCore.java:19) ~[?:?]
at tiance.auroracore.AuroraCore$1.run(AuroraCore.java:69) ~[?:?]
at org.bukkit.craftbukkit.v1_16_R3.scheduler.CraftTask.run(CraftTask.java:76) ~[craftbukkit-1.16.5.jar:3096a-Bukkit-af1a232]
at org.bukkit.craftbukkit.v1_16_R3.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:54) [craftbukkit-1.16.5.jar:3096a-Bukkit-af1a232]
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) [?:1.8.0_281]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) [?:1.8.0_281]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_281]
Caused by: java.lang.IllegalStateException: Initial initialization
at org.bukkit.plugin.java.PluginClassLoader.initialize(PluginClassLoader.java:221) ~[craftbukkit-1.16.5.jar:3096a-Bukkit-af1a232]
at org.bukkit.plugin.java.JavaPlugin.<init>(JavaPlugin.java:52) ~[craftbukkit-1.16.5.jar:3096a-Bukkit-af1a232]
at tiance.auroracore.AuroraCore.<init>(AuroraCore.java:19) ~[?:?]
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[?:1.8.0_281]
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source) ~[?:1.8.0_281]
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) ~[?:1.8.0_281]
at java.lang.reflect.Constructor.newInstance(Unknown Source) ~[?:1.8.0_281]
at java.lang.Class.newInstance(Unknown Source) ~[?:1.8.0_281]
at org.bukkit.plugin.java.PluginClassLoader.<init>(PluginClassLoader.java:79) ~[craftbukkit-1.16.5.jar:3096a-Bukkit-af1a232]
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:143) ~[craftbukkit-1.16.5.jar:3096a-Bukkit-af1a232]
at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:393) ~[craftbukkit-1.16.5.jar:3096a-Bukkit-af1a232]
at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:301) ~[craftbukkit-1.16.5.jar:3096a-Bukkit-af1a232]
at org.bukkit.craftbukkit.v1_16_R3.CraftServer.loadPlugins(CraftServer.java:379) ~[craftbukkit-1.16.5.jar:3096a-Bukkit-af1a232]
at net.minecraft.server.v1_16_R3.DedicatedServer.init(DedicatedServer.java:218) ~[craftbukkit-1.16.5.jar:3096a-Bukkit-af1a232]
at net.minecraft.server.v1_16_R3.MinecraftServer.w(MinecraftServer.java:905) ~[craftbukkit-1.16.5.jar:3096a-Bukkit-af1a232]
at net.minecraft.server.v1_16_R3.MinecraftServer.lambda$0(MinecraftServer.java:263) ~[craftbukkit-1.16.5.jar:3096a-Bukkit-af1a232]
... 1 more
I've edited the code again and again,but didn't found any solution. I've also seen some questions on the website, but none of them could solve my problem.I didn't found any repeat main class .I really don't know what to do! If someone can help, i will be very glad and thankful to him or her.

Replace new AuroraCore() with AuroraCore.this.

You have to replace new AuroraCore() with AuroraCore.this to initialize service() void
#Override
public void onEnable() {
new BukkitRunnable(){
public void run(){
AuroraCore.this.service();//调用service方法
}
}.runTaskAsynchronously(this);
int pluginId = 13929;
Metrics metrics = new Metrics(this, pluginId);
saveDefaultConfig();
}

getting error when compiling for modbus rs232

i am new in java... i am trying to read on modbus. PLC is slave device and it is configured well. my java file is unable to read modbus values.here is the code..given below. error is coming at master.init(); method. please help me in this case.
package com.mod4j;
import java.io.File;
import gnu.io.SerialPort;
import com.serotonin.io.serial.SerialParameters;
import com.serotonin.*;
import com.serotonin.modbus4j.ModbusFactory;
import com.serotonin.modbus4j.ModbusMaster;
import com.serotonin.modbus4j.code.DataType;
import com.serotonin.modbus4j.code.RegisterRange;
import com.serotonin.modbus4j.exception.ModbusInitException;
import com.serotonin.modbus4j.locator.BaseLocator;
import com.serotonin.modbus4j.locator.NumericLocator;
import com.serotonin.modbus4j.msg.ReadCoilsRequest;
import com.serotonin.modbus4j.msg.ReadCoilsResponse;
import com.serotonin.modbus4j.msg.ReadDiscreteInputsRequest;
import com.serotonin.modbus4j.msg.ReadHoldingRegistersRequest;
import com.serotonin.modbus4j.msg.ReadHoldingRegistersResponse;
import com.serotonin.modbus4j.msg.ReadInputRegistersRequest;
import com.serotonin.modbus4j.msg.ReadInputRegistersResponse;
import com.serotonin.modbus4j.msg.WriteCoilRequest;
import com.serotonin.modbus4j.msg.WriteCoilResponse;
import com.serotonin.modbus4j.msg.WriteRegistersRequest;
import com.serotonin.modbus4j.msg.WriteRegistersResponse;
import gnu.io.*;
public class Modbus4JTest
{
public static void main(String[] args) throws Exception
{
try
{
SerialParameters params = new SerialParameters();
params.setCommPortId("COM1");
params.setBaudRate(9600);
params.setDataBits(8);
params.setStopBits(1);
params.setParity(0);
ModbusFactory modbusFactory = new ModbusFactory();
ModbusMaster master = modbusFactory.createRtuMaster(params);
master.setTimeout(100);
master.setRetries(3);
byte [] RIR,RHR,RDI,RCR;
int slaveId=1;
int startOffset=0;
int numberOfRegisters=10;
int numberOfBits=10;
try
{
master.init();
while (true)
{
ReadInputRegistersRequest reqRIR = new ReadInputRegistersRequest(slaveId, startOffset, numberOfRegisters);
System.out.println("ReadInputRegistersRequest reqRIR =" +reqRIR);
ReadInputRegistersResponse resRIR = (ReadInputRegistersResponse) master.send(reqRIR);
RIR = resRIR.getData();
System.out.println("InputRegisters :" + RIR);
ReadHoldingRegistersRequest reqRHR = new ReadHoldingRegistersRequest(slaveId, startOffset, numberOfRegisters);
ReadHoldingRegistersResponse resRHR = (ReadHoldingRegistersResponse) master.send(reqRHR);
RHR=resRHR.getData();
System.out.println("HoldingRegister :" + RHR);
ReadDiscreteInputsRequest reqRDI= new ReadDiscreteInputsRequest(slaveId, startOffset, numberOfBits);
ReadCoilsResponse resRDI = (ReadCoilsResponse) master.send(reqRDI);
RDI=resRDI.getData();
System.out.println("DiscreteInput :" + RDI);
ReadCoilsRequest reqRCR = new ReadCoilsRequest(slaveId, startOffset, numberOfBits);
ReadCoilsResponse resRCR = (ReadCoilsResponse) master.send(reqRCR);
RCR=resRCR.getData();
System.out.println("CoilResponce :" + RCR);
short[] sdata = null;
WriteRegistersRequest reqWR = new WriteRegistersRequest(slaveId, startOffset, sdata);
WriteRegistersResponse resWR = (WriteRegistersResponse) master.send(reqWR);
int writeOffset = 0;
boolean writeValue = true;
WriteCoilRequest reqWC = new WriteCoilRequest(slaveId, writeOffset, writeValue);
WriteCoilResponse resWC = (WriteCoilResponse) master.send(reqWC);
Thread.sleep(1000);
}//end while
}//end try
catch (Exception e)
{
e.printStackTrace();
}//end catch
finally
{
master.destroy();
}//end finally
}//end try
catch (Exception e)
{
e.printStackTrace();
}//end catch
}// end main
}//end class Modbus4JTest
this is java file i am running.
and here are the error i have got after compiling..
please suggest what went wrong and please correct me at ...
is there any step by step tutorial or any demo video please give me link at
ayyaz.nadaf#gmail.com
Exception in thread "main" java.lang.NoClassDefFoundError:
jssc/SerialPortException
at com.serotonin.io.serial.SerialUtils.openSerialPort(SerialUtils.java:94)
at com.serotonin.modbus4j.serial.SerialMaster.init(SerialMaster.java:58)
at com.serotonin.modbus4j.serial.rtu.RtuMaster.init(RtuMaster.java:45)
at com.mod4j.Modbus4JTest.main(Modbus4JTest.java:58)
Caused by: java.lang.ClassNotFoundException: jssc.SerialPortException
at java.net.URLClassLoader$1.run(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
... 4 more

It appears you're using Modbus4J. It is based on jSSC (Java Simple Serial Connector) for serial communication, so make sure that jSSC is found while compiling (you may need to download it separately, since you're getting a ClassNotFoundException related to a jSSC class).
I don't know about any tutorial but I may suggest you to take a look at the Modbus4J forum archive. Here's a simple Modbus RTU example.

Exceptions with EJB3

I am Using a method in a session bean that is surrounded by a try and catch bloc with an IOException and it looks like it is making a problem as when i try to call a method from a java project client so here is my bean code
package com.et;
import com.gestionfichier.gestion.*;
import java.io.IOException;
import javax.ejb.ApplicationException;
import javax.ejb.Stateless;
#Stateless
public class PremierEJB3Bean implements PremierEJB3 {
public String envoicode(String Code) {
String s = null;
try {
s = GestionFichier.CopierCode(Code);
} catch (IOException e) {
e.printStackTrace();
}
CompilerFichierC.CompilerFichier(s,s);
return "Compilation réussie !";
}
}
and here is my client bean code:
package com.et;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
public class PremierEJB3Client {
public static void main(String[] args) {
try {
Context context = new InitialContext();
PremierEJB3 beanRemote = (PremierEJB3)
context.lookup("PremierEJB3Bean/remote");
System.out.println(beanRemote.envoicode("somthing"));
} catch (NamingException e) {
e.printStackTrace();
}
}
}
and here is what i get in the console
Exception in thread "main" java.lang.reflect.UndeclaredThrowableException
at $Proxy0.envoicode(Unknown Source)
at com.et.PremierEJB3Client.main(PremierEJB3Client.java:15)
Caused by: java.lang.ClassNotFoundException: [Ljava.lang.StackTraceElement;
at java.net.URLClassLoader$1.run(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
And more....
so i am quiet sure that exceptions in my bean are causing me this problem but i have no idea how to fix that

In order to do JNDI lookup for the EJB from a standalone client, context properties needs to be added.
Something similar to below.
Hashtable<String, String> ht = new Hashtable<String, String>();
ht.put(Context.INITIAL_CONTEXT_FACTORY, "weblogic.jndi.WLInitialContextFactory");
Context ct=new InitialContext(ht);

This doesn't necessarily indicate that the EJB bean is not found - a possible case would be that the bean is found, and its initializer is called in the EJB container, and an exception is caused there.
Thus you might see ClassNotFound - java.lang.StackTraceElement because somehow a serialized StackTraceElement is returned back to the client which cannot be de-serialized (e.g. because of an incompatibility between the Java version used to compile the code in the server and the code in the client?)
This was happening in my own scenario, where the EJB was found, but later when I called some method on it, a similar stack trace was appearing - because of an exception happening on the EJB container/server side. I fixed the error in the EJB and stopped looking for the reason its stack trace cannot be passed safely to the client.

Error when compiling code with the Protege API

I am new to Protege API and I have just created on Eclipse a small application which uses an external OWL file. Also I did import all the necessary libraries.
import java.util.Collection;
import java.util.Iterator;
import edu.stanford.smi.protege.exception.OntologyLoadException;
import edu.stanford.smi.protegex.owl.ProtegeOWL;
import edu.stanford.smi.protegex.owl.model.*;
public class Trial {
public static void main(String[] args) throws OntologyLoadException {
String uri = "C:/Documents and Settings/Anto/Desktop/travel.owl";
OWLModel owlModel = ProtegeOWL.createJenaOWLModelFromURI(uri);
Collection classes = owlModel.getUserDefinedOWLNamedClasses();
for (Iterator it = classes.iterator(); it.hasNext();) {
OWLNamedClass cls = (OWLNamedClass) it.next();
Collection instances = cls.getInstances(false);
System.out.println("Class " + cls.getBrowserText() + " ("
+ instances.size() + ")");
for (Iterator jt = instances.iterator(); jt.hasNext();) {
OWLIndividual individual = (OWLIndividual) jt.next();
System.out.println(" - " + individual.getBrowserText());
}
}
}
}
When I do compile however I get the following errors:
WARNING: [Local Folder Repository] The specified file must be a directory.
(C:\Documents and Settings\Anto\My Documents\Eclipse
Workspace\ProtegeTrial\plugins\edu.stanford.smi.protegex.owl)
LocalFolderRepository.update()
SEVERE: Exception caught -- java.net.URISyntaxException: Illegal character in path at
index 12: C:/Documents and Settings/CiuffreA/Desktop/travel.owl
at java.net.URI$Parser.fail(URI.java:2809)
at java.net.URI$Parser.checkChars(URI.java:2982)
at java.net.URI$Parser.parseHierarchical(URI.java:3066)
at java.net.URI$Parser.parse(URI.java:3014)
at java.net.URI.<init>(URI.java:578)
at edu.stanford.smi.protegex.owl.jena.JenaKnowledgeBaseFactory.getFileURI(Unknown Source)
at edu.stanford.smi.protegex.owl.jena.JenaKnowledgeBaseFactory.loadKnowledgeBase(Unknown Source)
at edu.stanford.smi.protege.model.Project.loadDomainKB(Unknown Source)
at edu.stanford.smi.protege.model.Project.createDomainKnowledgeBase(Unknown Source)
at edu.stanford.smi.protegex.owl.jena.creator.OwlProjectFromUriCreator.create(Unknown Source)
at edu.stanford.smi.protegex.owl.ProtegeOWL.createJenaOWLModelFromURI(Unknown Source)
at Trial.main(Trial.java:14)
Exception in thread "main" java.lang.NullPointerException
at edu.stanford.smi.protegex.owl.jena.JenaKnowledgeBaseFactory.loadKnowledgeBase(Unknown Source)
at edu.stanford.smi.protege.model.Project.loadDomainKB(Unknown Source)
at edu.stanford.smi.protege.model.Project.createDomainKnowledgeBase(Unknown Source)
at edu.stanford.smi.protegex.owl.jena.creator.OwlProjectFromUriCreator.create(Unknown Source)
at edu.stanford.smi.protegex.owl.ProtegeOWL.createJenaOWLModelFromURI(Unknown Source)
at Trial.main(Trial.java:14)
Does anyone have an idea on where the problem should be?

Replace
String uri = "C:/Documents and Settings/Anto/Desktop/travel.owl";
with
String uri = "file:///C:/Documents and Settings/Anto/Desktop/travel.owl";

Runtime Exception while executing Contacts Demo in Google Data API

I have downloaded the google data API plugin for eclipse. While dealing with the Contacts template (Demo.java)
/* INSTRUCTION: This is a command line application. So please execute this template with the following arguments:
arg[0] = username
arg[1] = password
*/
/**
* #author (Your Name Here)
*
*/
import com.google.gdata.client.contacts.ContactsService;
import com.google.gdata.data.contacts.ContactEntry;
import com.google.gdata.data.contacts.ContactFeed;
import com.google.gdata.util.AuthenticationException;
import com.google.gdata.util.ServiceException;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.List;
/**
* This is a test template
*/
public class Contacts {
public static void main(String[] args) {
try {
// Create a new Contacts service
ContactsService myService = new ContactsService("My Application");
myService.setUserCredentials(args[0],args[1]);
// Get a list of all entries
URL metafeedUrl = new URL("http://www.google.com/m8/feeds/contacts/"+args[0]+"#gmail.com/base");
System.out.println("Getting Contacts entries...\n");
ContactFeed resultFeed = myService.getFeed(metafeedUrl, ContactFeed.class);
List<ContactEntry> entries = resultFeed.getEntries();
for(int i=0; i<entries.size(); i++) {
ContactEntry entry = entries.get(i);
System.out.println("\t" + entry.getTitle().getPlainText());
}
System.out.println("\nTotal Entries: "+entries.size());
}
catch(AuthenticationException e) {
e.printStackTrace();
}
catch(MalformedURLException e) {
e.printStackTrace();
}
catch(ServiceException e) {
e.printStackTrace();
}
catch(IOException e) {
e.printStackTrace();
}
}
}
it is getting compiled successfully, but throwing this runtime exception (i am providing correct required credentials as arguments).
Exception in thread "main" java.lang.NoClassDefFoundError: com/google/common/collect/Maps
at com.google.gdata.wireformats.AltRegistry.<init>(AltRegistry.java:118)
at com.google.gdata.wireformats.AltRegistry.<init>(AltRegistry.java:100)
at com.google.gdata.client.Service.<clinit>(Service.java:532)
at Contacts.main(Contacts.java:36)
Caused by: java.lang.ClassNotFoundException: com.google.common.collect.Maps
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClassInternal(Unknown Source)
... 4 more
I am sure, i am missing something, but enable to resolve it.

You seem to be missing a dependency. Download this google-collections and add the jar to your build-path.