Add logfile to exception

SpigotCore_Main/src/de/steamwar/core/CheckpointUtils.java

@@ -30,9 +30,7 @@ import org.eclipse.openj9.criu.CRIUSupport;
 import org.eclipse.openj9.criu.JVMCRIUException;
 import sun.misc.Signal;
 
-import java.io.DataInputStream;
-import java.io.File;
-import java.io.IOException;
+import java.io.*;
 import java.net.InetAddress;
 import java.nio.file.FileSystems;
 import java.nio.file.Files;
@@ -109,6 +107,11 @@ public class CheckpointUtils {
             criu.checkpointJVM();
         } catch (JVMCRIUException e) {
             Bukkit.shutdown();
+
+            Path logfile = path.resolve("criu.log");
+            if(logfile.toFile().exists())
+                throw new IllegalStateException("Could not create checkpoint, criu log:\n" + new String(Files.readAllBytes(logfile)), e);
+
             throw e;
         }