Gradle Troubleshooting

When to Use This Skill
Quick Start
Instructions
Examples
Commands Reference
See Also

When to Use This Skill

Use this skill when you need to:

Debug OutOfMemoryError or heap space issues
Resolve dependency conflicts and version mismatches
Fix build cache or configuration cache problems
Diagnose slow build performance
Troubleshoot daemon or wrapper issues
Debug plugin loading failures
Resolve TestContainers or Docker connectivity issues
Investigate test failures in CI but not locally

Quick Start

When a build fails, run in order:

# 1. Stop daemon and clean
./gradlew --stop
./gradlew clean

# 2. Run with diagnostics
./gradlew build --stacktrace --info

# 3. If still failing, generate build scan
./gradlew build --scan

# 4. If slow, profile
./gradlew build --profile

Instructions

Step 1: Diagnose with Debug Output

Run with increasing verbosity to identify the issue:

# Stack trace (shows where error occurred)
./gradlew build --stacktrace

# Full stack trace (complete call stack)
./gradlew build --full-stacktrace

# Info logging (what Gradle is doing)
./gradlew build --info

# Debug logging (very detailed, generates lots of output)
./gradlew build --debug

# Use grep to filter
./gradlew build --info 2>&1 | grep -i error
./gradlew build --info 2>&1 | grep cache

Step 2: Identify the Issue Category

OutOfMemoryError:

./gradlew build 2>&1 | grep -i "outofmemory\|java heap\|metaspace"

Dependency resolution:

./gradlew dependencies --info 2>&1 | grep -i "could not\|failed\|error"
./gradlew dependencyInsight --dependency spring-core

Build cache problems:

./gradlew build --no-build-cache --info 2>&1 | grep cache

Configuration cache:

./gradlew build --no-configuration-cache --info

Plugin issues:

./gradlew build --stacktrace 2>&1 | grep -A 5 "plugin"

Step 3: Fix OutOfMemoryError

Immediate fix - Increase heap size:

# For this build only
./gradlew build -Dorg.gradle.jvmargs="-Xmx8g"

# Or stop daemon and increase persistent memory
./gradlew --stop

Permanent fix - Update gradle.properties:

# For standard projects (10-30 modules)
org.gradle.jvmargs=-Xmx4g -XX:MaxMetaspaceSize=1g -XX:+HeapDumpOnOutOfMemoryError -Dfile.encoding=UTF-8

# For large projects (30+ modules)
org.gradle.jvmargs=-Xmx8g -XX:MaxMetaspaceSize=2g -XX:+HeapDumpOnOutOfMemoryError -Dfile.encoding=UTF-8

# For very large projects
org.gradle.jvmargs=-Xmx12g -XX:MaxMetaspaceSize=3g -XX:+HeapDumpOnOutOfMemoryError -Dfile.encoding=UTF-8

Verify fix:

./gradlew --stop  # Must restart daemon
./gradlew build --info 2>&1 | grep "XX:Xmx"

Step 4: Debug Dependency Resolution

Understand why dependencies aren't resolving:

# Show full dependency tree
./gradlew dependencies

# Show specific configuration
./gradlew dependencies --configuration implementation

# Find where a dependency comes from
./gradlew dependencyInsight --dependency spring-core

# Show dependency insights for specific config
./gradlew dependencyInsight --dependency jackson-databind --configuration implementation

# Refresh and re-download
./gradlew build --refresh-dependencies

Common solutions:

Option 1: Force specific version:

// build.gradle.kts
configurations.all {
    resolutionStrategy {
        force("com.google.guava:guava:32.1.3-jre")
    }
}

Option 2: Exclude problematic transitive dependency:

dependencies {
    implementation("com.example:library:1.0") {
        exclude(group = "commons-logging", module = "commons-logging")
    }
}

Option 3: Use dependency constraints:

dependencies {
    constraints {
        implementation("org.apache.commons:commons-lang3:3.18.0")
    }
}

Step 5: Debug Build Cache Issues

Test if build cache is causing problems:

# Disable cache for this build
./gradlew build --no-build-cache

# If this fixes it, cache is the problem
# Clean cache
rm -rf ~/.gradle/caches/build-cache-*

# Check cache status
./gradlew build --build-cache --info | grep cache

# Verify task is cacheable
./gradlew build --info 2>&1 | grep "Cache key"

Common build cache issues:

Issue: Build slower with cache enabled

# Check for non-cacheable tasks
./gradlew build --info 2>&1 | grep -i "non-cacheable"

Issue: Incorrect cached results

# Clean entire cache
rm -rf ~/.gradle/caches

# Rebuild
./gradlew build

Step 6: Debug Configuration Cache

Test if configuration cache is compatible:

# Start with warnings (not errors)
./gradlew build --configuration-cache-problems=warn

# Check report
# build/reports/configuration-cache/<hash>/configuration-cache-report.html

# Once issues fixed, enable strict mode
./gradlew build --configuration-cache-problems=fail

Common configuration cache issues:

Issue: Build fails with configuration cache

# Disable temporarily
./gradlew build --no-configuration-cache

# Check for incompatible plugins
./gradlew build --configuration-cache-problems=warn --info

# View detailed report
open build/reports/configuration-cache/report.html

Issue: Plugins not compatible

# Update plugins to latest versions
./gradlew wrapper --gradle-version 9.2
./gradlew build -x test  # Skip tests temporarily

For advanced troubleshooting including slow build analysis, daemon management, wrapper issues, and plugin resolution, see references/advanced-troubleshooting.md.

Examples

Example 1: Complete Troubleshooting Workflow

# 1. Initial failure
./gradlew build
# BUILD FAILED

# 2. Get details
./gradlew build --stacktrace
# Shows: OutOfMemoryError: Java heap space

# 3. Fix: Update gradle.properties
echo "org.gradle.jvmargs=-Xmx4g -XX:MaxMetaspaceSize=1g" >> gradle.properties

# 4. Stop daemon and retry
./gradlew --stop
./gradlew build

# BUILD SUCCESSFUL

Example 2: Dependency Conflict Resolution

# Build fails with version conflict
./gradlew build
# ERROR: Could not resolve dependency: conflicting versions

# Investigate
./gradlew dependencyInsight --dependency commons-lang3

# You see:
# commons-lang3:3.8.1 <- old-library
# commons-lang3:3.18.0 <- new-library

# Solution: Force newer version
# In build.gradle.kts:
configurations.all {
    resolutionStrategy {
        force("org.apache.commons:commons-lang3:3.18.0")
    }
}

./gradlew build
# BUILD SUCCESSFUL

For advanced examples including slow build analysis, configuration cache debugging, and Docker troubleshooting, see references/advanced-examples.md.

Commands Reference

See references/commands-and-checklists.md for complete command reference, troubleshooting checklist, and quick reference table.