Debugging Tools and Techniques

IDE Debugging Tools

IntelliJ IDEA Debugger

IntelliJ IDEA provides powerful debugging capabilities:

• Breakpoints: Set breakpoints by clicking in the gutter area
• Debug Window: Access variables, watches, and call stack
• Evaluate Expression: Test code snippets during debugging
• Conditional Breakpoints: Set breakpoints that only trigger under specific conditions

Debug Toolbar

• Step Over (F8): Execute current line
• Step Into (F7): Enter method calls
• Step Out (Shift + F8): Complete current method
• Resume (F9): Continue until next breakpoint
• Stop (Ctrl + F2): End debugging session

Logging Tools

SLF4J with Logback

Example configuration and usage:

// Logger configuration
private static final Logger logger = LoggerFactory.getLogger(MyClass.class);

// Logging examples
logger.debug("Detailed information for debugging");
logger.info("General information about program execution");
logger.warn("Warning messages for potential problems");
logger.error("Error messages for serious issues");

Logback Configuration

<configuration>
    <appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender">
        <encoder>
            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
        </encoder>
    </appender>

    <root level="INFO">
        <appender-ref ref="CONSOLE" />
    </root>
</configuration>

Performance Profiling Tools

JProfiler

• CPU profiling
• Memory profiling
• Thread profiling
• Database profiling

VisualVM

• Monitor JVM performance
• Analyze memory usage
• Profile CPU usage
• Thread analysis

Memory Analysis Tools

JVM Tools

• jmap: Generate heap dumps
• jhat: Analyze heap dumps
• jstat: Monitor JVM statistics
• jstack: Print thread dumps

Eclipse Memory Analyzer (MAT)

• Analyze heap dumps
• Find memory leaks
• Generate memory reports
• Compare heap snapshots

Code Analysis Tools

Static Analysis

• SonarQube: Code quality and security analysis
• PMD: Static code analysis
• FindBugs: Bug pattern detection
• Checkstyle: Code style checking

Dynamic Analysis

• JaCoCo: Code coverage analysis
• JUnit: Unit testing framework
• Mockito: Mocking framework
• AssertJ: Fluent assertions