[12:48:17 ERROR]: Could not load 'plugins/HeartPlugin.jar' in folder 'plugins'

org.bukkit.plugin.InvalidPluginException: java.lang.NullPointerException

at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:135) ~[spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]

at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:329) ~[spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]

at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:251) [spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]

at org.bukkit.craftbukkit.v1_8_R3.CraftServer.loadPlugins(CraftServer.java:292) [spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]

at net.minecraft.server.v1_8_R3.DedicatedServer.init(DedicatedServer.java:198) [spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]

at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:525) [spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]

at java.lang.Thread.run(Thread.java:748) [?:1.8.0_212]

Caused by: java.lang.NullPointerException

at hertmanager.HeartScoreboard.<init>(HeartScoreboard.java:18) ~[?:?]

at hertmanager.Main.<init>(Main.java:16) ~[?:?]

at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[?:1.8.0_212]

at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[?:1.8.0_212]

at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[?:1.8.0_212]

at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[?:1.8.0_212]

at java.lang.Class.newInstance(Class.java:442) ~[?:1.8.0_212]

at org.bukkit.plugin.java.PluginClassLoader.<init>(PluginClassLoader.java:76) ~[spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]

at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:131) ~[spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]

... 6 more