Fix a few bugs in RMI server

Dockerfile

@@ -1,4 +1,4 @@
-FROM maven:3.5-jdk-8 as builder
+FROM maven:3.5-jdk-8 AS builder
 
 WORKDIR /app
 
@@ -13,7 +13,7 @@ COPY src ./src
 RUN mvn clean package -DskipTests
 RUN mv target/JNDI-Exploit-Kit-*-all.jar target/JNDI-Exploit-Kit.jar
 
-FROM openjdk:8-jdk-alpine
+FROM eclipse-temurin:8-jre-alpine
 
 WORKDIR /app
 

src/main/java/jndi/RMIRefServer.java

@@ -63,7 +63,7 @@
 public class RMIRefServer implements Runnable {
 
     public String command;
-    public String customScript;
+    public String customScript = "";
 
     private int port;
     private ServerSocket ss;

src/main/java/run/ServerStart.java

@@ -149,7 +149,7 @@ public static void main(String[] args) throws Exception {
 			Thread threadJetty = new Thread(servers.jettyServer);
 			threadJetty.start();
 
-			System.out.println(getLocalTime() + " [RMISERVER]  >> Listening on " + http_addr + ":" + rmiPort);
+			System.out.println(getLocalTime() + " [RMISERVER]  >> Listening on " + rmi_addr + ":" + rmiPort);
 			Thread threadRMI = new Thread(servers.rmiRefServer);
 			threadRMI.start();
 
@@ -289,4 +289,4 @@ public static String withColor(String str, String color) {
 		return str;
 	}
 
-}
+}