JVM Profiles

The --profile flag selects a set of optimized JVM flags for your workload.

Available Profiles

server (default)

Standard HotSpot behavior. No additional flags.

Best for:

• Long-running services

• Web servers

• Applications where throughput matters more than startup

Characteristics:

• Full tiered compilation (C1 → C2)

• G1GC (default garbage collector)

• Higher memory overhead

• Peak performance after warmup

cli

Optimized for short-lived processes and CLI tools.

Best for:

• Command-line tools

• Scripts

• One-shot utilities

• Serverless functions

Characteristics:

• Tiered compilation with C1 only (skip C2)

• SerialGC (simpler, faster startup)

• Reduced code cache

• ~200-350ms startup (with AppCDS)

Usage

# CLI profile
jbundle build --input . --output ./dist/app --profile cli

# Server profile (default)
jbundle build --input . --output ./dist/app --profile server

Or in jbundle.toml:

profile = "cli"

Performance Comparison

Metric	cli	server
Startup (cold)	~800-1500ms	~1000-2000ms
Startup (warm)	~200-350ms	~400-600ms
Peak throughput	Lower	Higher
Memory footprint	Lower	Higher
Warmup time	Faster	Slower

When to Use Each

cli profile:
  ✓ Run once and exit
  ✓ Interactive commands
  ✓ Scripts and automation
  ✓ Startup time is critical

server profile:
  ✓ Long-running processes
  ✓ Web servers
  ✓ Background services
  ✓ Throughput is critical

Combining with AppCDS and CRaC

Profiles work alongside other optimizations:

# CLI + AppCDS (default) → ~200-350ms
jbundle build --input . --output ./app --profile cli

# CLI + CRaC → ~10-50ms (Linux only)
jbundle build --input . --output ./app --profile cli --crac

# Server + no AppCDS → standard JVM startup
jbundle build --input . --output ./app --profile server --no-appcds