教程说我只需要将它们放在maven上：
<repository>
<id>mercadopago</id>
<url>https://github.com/mercadopago/sdk-java/raw/master/releases</url>
</repository>
<dependency>
<groupId>com.mercadopago</groupId>
<artifactId>sdk</artifactId>
<version>0.3.4</version>
</dependency>
API（is available from npm）
我做到了，但我收到了这个错误：
java.lang.NoClassDefFoundError: com/mercadopago/MP
at io.github.margato.vippago.Main.onEnable(Main.java:31)
at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:217)
at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:457)
at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:382)
at org.bukkit.craftbukkit.v1_5_R3.CraftServer.loadPlugin(CraftServer.java:305)
at org.bukkit.craftbukkit.v1_5_R3.CraftServer.enablePlugins(CraftServer.java:287)
at org.bukkit.craftbukkit.v1_5_R3.CraftServer.reload(CraftServer.java:630)
at org.bukkit.Bukkit.reload(Bukkit.java:275)
at org.bukkit.command.defaults.ReloadCommand.execute(ReloadCommand.java:24)
at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:189)
at org.bukkit.craftbukkit.v1_5_R3.CraftServer.dispatchCommand(CraftServer.java:546)
at org.bukkit.craftbukkit.v1_5_R3.CraftServer.dispatchServerCommand(CraftServer.java:535)
at net.minecraft.server.v1_5_R3.DedicatedServer.an(DedicatedServer.java:263)
at net.minecraft.server.v1_5_R3.DedicatedServer.r(DedicatedServer.java:228)
at net.minecraft.server.v1_5_R3.MinecraftServer.q(MinecraftServer.java:472)
at net.minecraft.server.v1_5_R3.MinecraftServer.run(MinecraftServer.java:404)
at net.minecraft.server.v1_5_R3.ThreadServerApplication.run(SourceFile:573)
Caused by: java.lang.ClassNotFoundException: com.mercadopago.MP
at java.net.URLClassLoader.findClass(Unknown Source)
at org.bukkit.plugin.java.PluginClassLoader.findClass0(PluginClassLoader.java:80)
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:53)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
... 17 more
我该怎么做？