Eclipse PDE - While creating XWT component and adding to Palette, End user sees the component twice when dragged and dropped

You create an XWT composite component, say button and name it as 'MyButton', then the wizard creates 2 files for you. One is MyButton.xwt and other one MyButton.java.
You will add the new component into palette by normal 'add component' wizard and it is ready for end user to be dragged and dropped.

But when an user drags and drops the 'MyButton' component from palette, it appears twice on UI.

Reason: Actually the two fies '.xwt' and '.java', both files would have the initialization routine by default. so when 'MyButton' component was dropped, both of them initialized and showed twice. Ideally '.java' file should be used as a handler to handle the events from UI. So To solve it, delete the initialization routine written inside the constructor of 'MyButton.java' file. That should fix this problem.
Another reason that might contribute to the double appearance is name of a property matching to parent class. Suppose inside MyButton.java file, you declare a property called 'size' and write getter/setter for this. Purpose of such property is to customize 'size' property and show 'size' property whenever user clicks on 'MyButton' component. BUT originally there is already a 'size' property in parent class...so when you write 'size' and build your component, It will show up twice when user drops the component from palette. You can rename your 'size' property to any other string...And that should fix this problem too. 

Maven build error Error transferring file: Permission denied: connect

Problem: When you try to do a maven build, then it tries to download all POM files or JAR files from maven repo, and it throws following error:
Error transferring file: Permission denied: connect

It is not able to download even 1 file from maven repo.

This is the complete stack trace when run with -X option:


E:\LearningProjects>mvn -X archetype:generate  -DarchetypeGroupId=org.apache.maven.archetypes -DgroupId=com.mycompany.app -Dartifa
ctId=my-app
+ Error stacktraces are turned on.
Apache Maven 2.2.1 (r801777; 2009-08-07 00:46:01+0530)
Java version: 1.6.0_27
Java home: C:\Program Files\Java\jdk1.6.0_27\jre
Default locale: en_US, platform encoding: Cp1252
OS name: "windows 7" version: "6.1" arch: "amd64" Family: "windows"
[DEBUG] Building Maven user-level plugin registry from: 'C:\Users\testuser\.m2\plugin-registry.xml'
[DEBUG] Building Maven global-level plugin registry from: 'C:\Users\testuser\apache-maven-2.2.1\bin\..\conf\plugin-registry.xml'
[INFO] Scanning for projects...
[INFO] Searching repository for plugin with prefix: 'archetype'.
[DEBUG] Loading plugin prefixes from group: org.apache.maven.plugins
[INFO] org.apache.maven.plugins: checking for updates from central
[DEBUG] Using Wagon implementation lightweight from default mapping for protocol http
[DEBUG] Checking for pre-existing User-Agent configuration.
[DEBUG] Adding User-Agent configuration.
[DEBUG] Connecting to repository: 'central' with url: 'http://repo1.maven.org/maven2'.
[DEBUG] Using Wagon implementation lightweight from default mapping for protocol http
[WARNING] repository metadata for: 'org.apache.maven.plugins' could not be retrieved from repository: central due to an error: Err
or transferring file: Permission denied: connect
[DEBUG] Exception
org.apache.maven.wagon.TransferFailedException: Error transferring file: Permission denied: connect
        at org.apache.maven.wagon.providers.http.LightweightHttpWagon.fillInputData(LightweightHttpWagon.java:143)
        at org.apache.maven.wagon.StreamWagon.getInputStream(StreamWagon.java:116)
        at org.apache.maven.wagon.StreamWagon.getIfNewer(StreamWagon.java:88)
        at org.apache.maven.wagon.StreamWagon.get(StreamWagon.java:61)
        at org.apache.maven.artifact.manager.DefaultWagonManager.getRemoteFile(DefaultWagonManager.java:546)
        at org.apache.maven.artifact.manager.DefaultWagonManager.getArtifactMetadata(DefaultWagonManager.java:443)
        at org.apache.maven.artifact.repository.metadata.DefaultRepositoryMetadataManager.resolve(DefaultRepositoryMetadataManager
.java:97)
        at org.apache.maven.plugin.DefaultPluginMappingManager.loadPluginMappings(DefaultPluginMappingManager.java:103)
        at org.apache.maven.plugin.DefaultPluginMappingManager.loadPluginMappings(DefaultPluginMappingManager.java:87)
        at org.apache.maven.plugin.DefaultPluginMappingManager.getByPrefix(DefaultPluginMappingManager.java:61)
        at org.apache.maven.plugin.DefaultPluginManager.getPluginDefinitionForPrefix(DefaultPluginManager.java:159)
        at org.apache.maven.lifecycle.DefaultLifecycleExecutor.getMojoDescriptor(DefaultLifecycleExecutor.java:1801)
        at org.apache.maven.lifecycle.DefaultLifecycleExecutor.segmentTaskListByAggregationNeeds(DefaultLifecycleExecutor.java:462
)
        at org.apache.maven.lifecycle.DefaultLifecycleExecutor.execute(DefaultLifecycleExecutor.java:175)
        at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:328)
        at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:138)
        at org.apache.maven.cli.MavenCli.main(MavenCli.java:362)
        at org.apache.maven.cli.compat.CompatibleMain.main(CompatibleMain.java:60)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at org.codehaus.classworlds.Launcher.launchEnhanced(Launcher.java:315)
        at org.codehaus.classworlds.Launcher.launch(Launcher.java:255)
        at org.codehaus.classworlds.Launcher.mainWithExitCode(Launcher.java:430)
        at org.codehaus.classworlds.Launcher.main(Launcher.java:375)
Caused by: java.net.SocketException: Permission denied: connect
        at java.net.PlainSocketImpl.socketConnect(Native Method)
        at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:351)
        at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:213)
        at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:200)
        at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
        at java.net.Socket.connect(Socket.java:529)
        at java.net.Socket.connect(Socket.java:478)
        at sun.net.NetworkClient.doConnect(NetworkClient.java:163)
        at sun.net.www.http.HttpClient.openServer(HttpClient.java:395)
        at sun.net.www.http.HttpClient.openServer(HttpClient.java:530)
        at sun.net.www.http.HttpClient.<init>(HttpClient.java:234)
        at sun.net.www.http.HttpClient.New(HttpClient.java:307)
        at sun.net.www.http.HttpClient.New(HttpClient.java:324)
        at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:970)
        at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:911)
        at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:836)
        at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1172)
        at java.net.HttpURLConnection.getResponseCode(HttpURLConnection.java:379)
        at org.apache.maven.wagon.providers.http.LightweightHttpWagon.fillInputData(LightweightHttpWagon.java:115)
        ... 25 more
[INFO] Repository 'central' will be blacklisted
[DEBUG] Loading plugin prefixes from group: org.codehaus.mojo
[DEBUG] Skipping blacklisted repository central
[DEBUG] Skipping blacklisted repository central
[DEBUG] maven-archetype-plugin: using locally installed snapshot
[DEBUG] Artifact not found - using stub model: Unable to determine the latest version

  org.apache.maven.plugins:maven-archetype-plugin:pom:LATEST



[DEBUG] Using defaults for missing POM org.apache.maven.plugins:maven-archetype-plugin:pom:LATEST
[DEBUG] maven-archetype-plugin: using locally installed snapshot
[DEBUG] Artifact not found - using stub model: Unable to determine the release version

  org.apache.maven.plugins:maven-archetype-plugin:pom:RELEASE



[DEBUG] Using defaults for missing POM org.apache.maven.plugins:maven-archetype-plugin:pom:RELEASE
[INFO] ------------------------------------------------------------------------
[ERROR] BUILD ERROR
[INFO] ------------------------------------------------------------------------
[INFO] The plugin 'org.apache.maven.plugins:maven-archetype-plugin' does not exist or no valid version could be found
[INFO] ------------------------------------------------------------------------
[DEBUG] Trace
org.apache.maven.lifecycle.LifecycleExecutionException: The plugin 'org.apache.maven.plugins:maven-archetype-plugin' does not exis
t or no valid version could be found
        at org.apache.maven.lifecycle.DefaultLifecycleExecutor.verifyPlugin(DefaultLifecycleExecutor.java:1569)
        at org.apache.maven.lifecycle.DefaultLifecycleExecutor.getMojoDescriptor(DefaultLifecycleExecutor.java:1851)
        at org.apache.maven.lifecycle.DefaultLifecycleExecutor.segmentTaskListByAggregationNeeds(DefaultLifecycleExecutor.java:462
)
        at org.apache.maven.lifecycle.DefaultLifecycleExecutor.execute(DefaultLifecycleExecutor.java:175)
        at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:328)
        at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:138)
        at org.apache.maven.cli.MavenCli.main(MavenCli.java:362)
        at org.apache.maven.cli.compat.CompatibleMain.main(CompatibleMain.java:60)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at org.codehaus.classworlds.Launcher.launchEnhanced(Launcher.java:315)
        at org.codehaus.classworlds.Launcher.launch(Launcher.java:255)
        at org.codehaus.classworlds.Launcher.mainWithExitCode(Launcher.java:430)
        at org.codehaus.classworlds.Launcher.main(Launcher.java:375)
Caused by: org.apache.maven.plugin.version.PluginVersionNotFoundException: The plugin 'org.apache.maven.plugins:maven-archetype-pl
ugin' does not exist or no valid version could be found
        at org.apache.maven.plugin.version.DefaultPluginVersionManager.resolvePluginVersion(DefaultPluginVersionManager.java:229)
        at org.apache.maven.plugin.version.DefaultPluginVersionManager.resolvePluginVersion(DefaultPluginVersionManager.java:91)
        at org.apache.maven.plugin.DefaultPluginManager.verifyPlugin(DefaultPluginManager.java:179)
        at org.apache.maven.plugin.DefaultPluginManager.loadPluginDescriptor(DefaultPluginManager.java:1642)
        at org.apache.maven.lifecycle.DefaultLifecycleExecutor.verifyPlugin(DefaultLifecycleExecutor.java:1540)
        ... 15 more
[INFO] ------------------------------------------------------------------------
[INFO] Total time: < 1 second
[INFO] Finished at: Fri Jan 06 20:02:54 IST 2012
[INFO] Final Memory: 2M/121M
[INFO] ------------------------------------------------------------------------



Solution: I tried almost everything found on net for almost 2 days, that did not work. Initially i was trying to build with maven 3.x version, seeing
this error, i switched to maven2.x, but still same error. Initially i was using jdk1.7, then i downgraded to jdk 1.6 but that also did not solve the problem.
My OS was win7 64 bit and i heard somewhere about java 32 bit and 64 bit. I downloaded both 32 and 64 bit java, modified all environment variables but still
same issue persisted. Somewhere i read about Windows Firewall enabling/disabling. I enabled/disabled Firewall, allowed java/http through allowed programs,
but that also did not fix the issue. I use a wireless router to route the network connection got from my ISP. I even removed that connection and tried to
use the IP directly by my system (since the router was giving me local IP such as 192.168.1.2 and i though that might be problem), but still same issue :(.
At last what fixed it, is interesting: I had purchased a new system which had Intel motherboard. There was in-built antivirus and Firewall installed with it.
When i disabled 'Personal Firewall' from that ESET security options. Then maven started downloading everything and built successfully.

Interestingly, this fixed other couple of issues: such as running IE 64 bit version and downloading files using torrent.