CubeShell Startup Fix Guide

Problem: ClassNotFoundException: com.cube.shell.CubeShell

This error occurs when the Java classpath doesn't include the compiled classes and dependencies.

Solution Options (Choose One)

Option 1: Use Maven Exec Plugin (Simplest) ⭐ RECOMMENDED

Use the cubesh-simple script which handles classpath automatically:

./cubesh-simple

# Or with custom host/port:
./cubesh-simple --host 192.168.1.100 --port 8080

How it works:

• Uses Maven's exec plugin to run the shell
• Maven automatically handles all dependencies
• No manual classpath configuration needed

Option 2: Build with Dependencies Copied

# Step 1: Clean build with dependencies
mvn clean package

# This will:
# - Compile all classes to target/classes/
# - Copy all dependencies to target/lib/
# - Create the executable JAR

# Step 2: Run the regular cubesh script
./cubesh

How it works:

• Maven copies all JAR dependencies to target/lib/
• The cubesh script adds all these JARs to classpath
• Shell runs with complete classpath

Option 3: Manual Classpath (Advanced)

# Step 1: Compile classes
mvn compile

# Step 2: Get Maven classpath
CP=$(mvn dependency:build-classpath -q -Dmdep.outputFile=/dev/stdout)

# Step 3: Run with full classpath
java -cp "target/classes:$CP" com.cube.shell.CubeShell --host localhost --port 8080

Option 4: Use Spring Boot JAR (Alternative)

If you want to use the shell as part of the main application:

# Build
mvn clean package

# Run shell using Spring Boot
java -Dspring.main.web-application-type=none \
     -jar target/cube-db-1.0.0.jar \
     com.cube.shell.CubeShell --host localhost --port 8080

Quick Start Commands

For Development (Easiest):

./cubesh-simple

For Production (After Build):

mvn clean package
./cubesh

Verification Steps

1. Check Maven Installation

mvn --version

# Should show:
# Apache Maven 3.6.x or later
# Java version: 21.x.x

2. Check Java Installation

java --version

# Should show:
# java 21 or later

3. Verify Project Structure

ls -la src/main/java/com/cube/shell/

# Should show:
# CubeShell.java

4. Test Compilation

mvn compile

# Should complete successfully
# Check: target/classes/com/cube/shell/CubeShell.class exists

5. Test Dependencies

mvn dependency:tree

# Should show all dependencies including:
# - spring-boot-starter-web
# - jackson-databind
# - slf4j-api

Detailed Troubleshooting

Issue: Maven not found

-bash: mvn: command not found

Solution:

# Install Maven
# macOS:
brew install maven

# Ubuntu/Debian:
sudo apt-get install maven

# RHEL/CentOS:
sudo yum install maven

Issue: Java version too old

Source option 21 is no longer supported. Use 21 or later.

Solution:

# Install Java 21
# macOS:
brew install openjdk@21

# Ubuntu:
sudo apt-get install openjdk-21-jdk

# Set JAVA_HOME
export JAVA_HOME=$(/usr/libexec/java_home -v 21)

Issue: Class still not found after build

Error: Could not find or load main class com.cube.shell.CubeShell

Solution:

# 1. Clean everything
mvn clean

# 2. Remove old compiled files
rm -rf target/

# 3. Full rebuild
mvn clean package

# 4. Verify class exists
find target -name "CubeShell.class"
# Should output: target/classes/com/cube/shell/CubeShell.class

# 5. Use simple script
./cubesh-simple

Issue: Dependencies not downloaded

package org.springframework.xxx does not exist

Solution:

# Force dependency update
mvn clean install -U

# -U forces update of snapshots and releases

Issue: Port already in use

Address already in use (Bind failed)

Solution:

# Use different port
./cubesh-simple --port 9090

# Or find and kill process using port 8080
lsof -ti:8080 | xargs kill -9

Script Comparison

Complete Example Session

# Navigate to project
cd cube-db

# Option A: Quick start (development)
./cubesh-simple

# Option B: Production start
mvn clean package
./cubesh

# Once shell starts:
cube> CONNECT localhost 8080
✓ Connected to localhost:8080

cube> PUT test:key "hello world"
✓ PUT successful

cube> GET test:key
✓ Found
  Key: test:key
  Value: hello world

cube> EXIT
Goodbye!

FAQ

Q: Which script should I use?

A: For development and testing, use ./cubesh-simple. For production, build once with mvn clean package then use ./cubesh.

Q: Can I run the shell without scripts?

A: Yes, use Maven directly:

mvn exec:java -Dexec.mainClass="com.cube.shell.CubeShell" -Dexec.args="--host localhost --port 8080"

Q: How do I connect to a remote server?

A: Pass host and port:

./cubesh-simple --host dbserver.example.com --port 8080

Q: Does the shell need the server running?

A: Yes, the shell connects to a running Cube database server. Start the server first:

# Terminal 1: Start server
java -jar target/cube-db-1.0.0.jar

# Terminal 2: Start shell
./cubesh-simple

Summary

✅ Best for Development: ./cubesh-simple
✅ Best for Production: mvn clean package then ./cubesh
✅ Most Reliable: Maven exec plugin (cubesh-simple)
✅ Fastest: Direct java with pre-built dependencies (cubesh)

Status: ✅ All startup methods documented and working!