List<MyClass> class; Problem.

Hi!

In my code i have 2 classes, UserManager and User. UserManager contain a of user. List<User> users; and get/set to it.

I have a function in UserManager called "public User getUser(String user)":

Code:

public User getUser(String name) {
    for (int i = 0; i < users.size(); i++) {
        User u = users.get(i);

        if (u.getName().equalsIgnoreCase(name)) {
            return u;
        }
     }   
     return null;
}

When i try to get user using this function:

Code:

UserManager um;
UserManager.getUser(String name);

I get this error:

Code:

2011-04-11 19:53:11 [SEVERE] null
org.bukkit.command.CommandException: Unhandled exception executing command 'lc' in plugin LocalChat v0.3
    at org.bukkit.command.PluginCommand.execute(PluginCommand.java:37)
    at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:80)
    at org.bukkit.craftbukkit.CraftServer.dispatchCommand(CraftServer.java:254)
    at net.minecraft.server.NetServerHandler.c(NetServerHandler.java:596)
    at net.minecraft.server.NetServerHandler.chat(NetServerHandler.java:559)
    at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:553)
    at net.minecraft.server.Packet3Chat.a(SourceFile:24)
    at net.minecraft.server.NetworkManager.a(NetworkManager.java:198)
    at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:72)
    at net.minecraft.server.NetworkListenThread.a(SourceFile:100)
    at net.minecraft.server.MinecraftServer.h(MinecraftServer.java:368)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:283)
    at net.minecraft.server.ThreadServerApplication.run(SourceFile:375)
Caused by: java.lang.NullPointerException
    at com.halvors.LocalChat.user.UserManager.getUser(UserManager.java:31)
    at com.halvors.LocalChat.LocalChatCommandExecutor.showStatus(LocalChatCommandExecutor.java:227)
    at com.halvors.LocalChat.LocalChatCommandExecutor.onCommand(LocalChatCommandExecutor.java:59)
    at org.bukkit.command.PluginCommand.execute(PluginCommand.java:35)
    ... 12 more

Hope anybody could help me svolve this

If you need to look at my Source Code it's here: https://github.com/halvors/LocalChat

Thanks

 

You might as well want to use a HashMap...

 

Have to store more values than 1 so have to use a class.

 

Your problem is that you either have a null entry in your users List (check all location where you use UserManager.addUser() if they could have put that null entry in the users list) or that one of the users in that list doesn't have a name set (User.getName() = null).