Published on Sun Jun 15 2025 10:00:00 GMT+0000 (Coordinated Universal Time) by Purusothaman Ramanujam

System Utilities in Apache Commons Lang

Introduction

Working with system information, detecting operating systems, and handling platform-specific code are common requirements in Java applications. Apache Commons Lang’s SystemUtils provides a comprehensive set of utilities that make system operations more convenient, cross-platform, and robust.

In this comprehensive guide, you’ll learn how to use SystemUtils effectively with detailed examples and real-world use cases.

Adding Apache Commons Lang to Your Project

Maven Dependency

<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-lang3</artifactId>
    <version>3.13.0</version>
</dependency>

Gradle Dependency

implementation 'org.apache.commons:commons-lang3:3.13.0'

Basic System Information

Operating System Detection

import org.apache.commons.lang3.SystemUtils;

public class SystemUtilsBasics {
    public static void main(String[] args) {
        // Operating system detection
        System.out.println("OS Name: " + SystemUtils.OS_NAME);
        System.out.println("OS Version: " + SystemUtils.OS_VERSION);
        System.out.println("OS Architecture: " + SystemUtils.OS_ARCH);

        // Platform-specific boolean flags
        System.out.println("Is Windows: " + SystemUtils.IS_OS_WINDOWS);
        System.out.println("Is Linux: " + SystemUtils.IS_OS_LINUX);
        System.out.println("Is macOS: " + SystemUtils.IS_OS_MAC);
        System.out.println("Is Unix: " + SystemUtils.IS_OS_UNIX);

        // More specific OS detection
        System.out.println("Is Windows 10: " + SystemUtils.IS_OS_WINDOWS_10);
        System.out.println("Is Windows 11: " + SystemUtils.IS_OS_WINDOWS_11);
        System.out.println("Is macOS X: " + SystemUtils.IS_OS_MAC_OSX);
        System.out.println("Is macOS X Cheetah: " + SystemUtils.IS_OS_MAC_OSX_CHEETAH);
    }
}

Java Runtime Information

public class JavaRuntimeInfo {
    public static void main(String[] args) {
        // Java version information
        System.out.println("Java Version: " + SystemUtils.JAVA_VERSION);
        System.out.println("Java Vendor: " + SystemUtils.JAVA_VENDOR);
        System.out.println("Java Vendor URL: " + SystemUtils.JAVA_VENDOR_URL);

        // Java home and class path
        System.out.println("Java Home: " + SystemUtils.JAVA_HOME);
        System.out.println("Java Class Path: " + SystemUtils.JAVA_CLASS_PATH);
        System.out.println("Java Class Version: " + SystemUtils.JAVA_CLASS_VERSION);

        // Java specification
        System.out.println("Java Specification Name: " + SystemUtils.JAVA_SPECIFICATION_NAME);
        System.out.println("Java Specification Vendor: " + SystemUtils.JAVA_SPECIFICATION_VENDOR);
        System.out.println("Java Specification Version: " + SystemUtils.JAVA_SPECIFICATION_VERSION);

        // Java runtime
        System.out.println("Java Runtime Name: " + SystemUtils.JAVA_RUNTIME_NAME);
        System.out.println("Java Runtime Vendor: " + SystemUtils.JAVA_RUNTIME_VENDOR);
        System.out.println("Java Runtime Version: " + SystemUtils.JAVA_RUNTIME_VERSION);
    }
}

Advanced System Detection

Detailed OS Information

public class DetailedOSInfo {
    public static void main(String[] args) {
        // File separator and path separator
        System.out.println("File Separator: " + SystemUtils.FILE_SEPARATOR);
        System.out.println("Path Separator: " + SystemUtils.PATH_SEPARATOR);
        System.out.println("Line Separator: " + SystemUtils.LINE_SEPARATOR);

        // User information
        System.out.println("User Name: " + SystemUtils.USER_NAME);
        System.out.println("User Home: " + SystemUtils.USER_HOME);
        System.out.println("User Directory: " + SystemUtils.USER_DIR);
        System.out.println("User Language: " + SystemUtils.USER_LANGUAGE);
        System.out.println("User Country: " + SystemUtils.USER_COUNTRY);
        System.out.println("User Timezone: " + SystemUtils.USER_TIMEZONE);

        // System properties
        System.out.println("System Name: " + SystemUtils.USER_NAME);
        System.out.println("System Architecture: " + SystemUtils.OS_ARCH);
        System.out.println("System Model: " + SystemUtils.OS_NAME + " " + SystemUtils.OS_VERSION);
    }
}

Platform-Specific Detection

public class PlatformDetection {
    public static void main(String[] args) {
        // Windows variants
        System.out.println("Is Windows 95: " + SystemUtils.IS_OS_WINDOWS_95);
        System.out.println("Is Windows 98: " + SystemUtils.IS_OS_WINDOWS_98);
        System.out.println("Is Windows ME: " + SystemUtils.IS_OS_WINDOWS_ME);
        System.out.println("Is Windows NT: " + SystemUtils.IS_OS_WINDOWS_NT);
        System.out.println("Is Windows 2000: " + SystemUtils.IS_OS_WINDOWS_2000);
        System.out.println("Is Windows XP: " + SystemUtils.IS_OS_WINDOWS_XP);
        System.out.println("Is Windows Vista: " + SystemUtils.IS_OS_WINDOWS_VISTA);
        System.out.println("Is Windows 7: " + SystemUtils.IS_OS_WINDOWS_7);
        System.out.println("Is Windows 8: " + SystemUtils.IS_OS_WINDOWS_8);
        System.out.println("Is Windows 10: " + SystemUtils.IS_OS_WINDOWS_10);
        System.out.println("Is Windows 11: " + SystemUtils.IS_OS_WINDOWS_11);

        // Unix variants
        System.out.println("Is Unix: " + SystemUtils.IS_OS_UNIX);
        System.out.println("Is Linux: " + SystemUtils.IS_OS_LINUX);
        System.out.println("Is AIX: " + SystemUtils.IS_OS_AIX);
        System.out.println("Is HP-UX: " + SystemUtils.IS_OS_HP_UX);
        System.out.println("Is Irix: " + SystemUtils.IS_OS_IRIX);
        System.out.println("Is Solaris: " + SystemUtils.IS_OS_SOLARIS);
        System.out.println("Is SunOS: " + SystemUtils.IS_OS_SUN_OS);

        // macOS variants
        System.out.println("Is macOS: " + SystemUtils.IS_OS_MAC);
        System.out.println("Is macOS X: " + SystemUtils.IS_OS_MAC_OSX);
        System.out.println("Is macOS X Cheetah: " + SystemUtils.IS_OS_MAC_OSX_CHEETAH);
        System.out.println("Is macOS X Puma: " + SystemUtils.IS_OS_MAC_OSX_PUMA);
        System.out.println("Is macOS X Jaguar: " + SystemUtils.IS_OS_MAC_OSX_JAGUAR);
        System.out.println("Is macOS X Panther: " + SystemUtils.IS_OS_MAC_OSX_PANTHER);
        System.out.println("Is macOS X Tiger: " + SystemUtils.IS_OS_MAC_OSX_TIGER);
        System.out.println("Is macOS X Leopard: " + SystemUtils.IS_OS_MAC_OSX_LEOPARD);
        System.out.println("Is macOS X Snow Leopard: " + SystemUtils.IS_OS_MAC_OSX_SNOW_LEOPARD);
        System.out.println("Is macOS X Lion: " + SystemUtils.IS_OS_MAC_OSX_LION);
        System.out.println("Is macOS X Mountain Lion: " + SystemUtils.IS_OS_MAC_OSX_MOUNTAIN_LION);
        System.out.println("Is macOS X Mavericks: " + SystemUtils.IS_OS_MAC_OSX_MAVERICKS);
        System.out.println("Is macOS X Yosemite: " + SystemUtils.IS_OS_MAC_OSX_YOSEMITE);
        System.out.println("Is macOS X El Capitan: " + SystemUtils.IS_OS_MAC_OSX_EL_CAPITAN);
        System.out.println("Is macOS X Sierra: " + SystemUtils.IS_OS_MAC_OSX_SIERRA);
        System.out.println("Is macOS X High Sierra: " + SystemUtils.IS_OS_MAC_OSX_HIGH_SIERRA);
        System.out.println("Is macOS X Mojave: " + SystemUtils.IS_OS_MAC_OSX_MOJAVE);
        System.out.println("Is macOS X Catalina: " + SystemUtils.IS_OS_MAC_OSX_CATALINA);
        System.out.println("Is macOS X Big Sur: " + SystemUtils.IS_OS_MAC_OSX_BIG_SUR);
        System.out.println("Is macOS X Monterey: " + SystemUtils.IS_OS_MAC_OSX_MONTEREY);
        System.out.println("Is macOS X Ventura: " + SystemUtils.IS_OS_MAC_OSX_VENTURA);
        System.out.println("Is macOS X Sonoma: " + SystemUtils.IS_OS_MAC_OSX_SONOMA);
    }
}

Real-World Examples

Cross-Platform File Operations

import java.io.File;
import java.nio.file.Path;
import java.nio.file.Paths;

public class CrossPlatformFileOps {
    public static String getConfigPath() {
        String configDir;

        if (SystemUtils.IS_OS_WINDOWS) {
            configDir = SystemUtils.USER_HOME + "\\AppData\\Local\\MyApp\\config";
        } else if (SystemUtils.IS_OS_MAC) {
            configDir = SystemUtils.USER_HOME + "/Library/Application Support/MyApp/config";
        } else {
            // Linux and other Unix systems
            configDir = SystemUtils.USER_HOME + "/.config/myapp";
        }

        return configDir;
    }

    public static String getLogPath() {
        String logDir;

        if (SystemUtils.IS_OS_WINDOWS) {
            logDir = SystemUtils.USER_HOME + "\\AppData\\Local\\MyApp\\logs";
        } else if (SystemUtils.IS_OS_MAC) {
            logDir = SystemUtils.USER_HOME + "/Library/Logs/MyApp";
        } else {
            // Linux and other Unix systems
            logDir = SystemUtils.USER_HOME + "/.local/share/myapp/logs";
        }

        return logDir;
    }

    public static String getTempPath() {
        return SystemUtils.JAVA_IO_TMPDIR;
    }

    public static void main(String[] args) {
        System.out.println("Config Path: " + getConfigPath());
        System.out.println("Log Path: " + getLogPath());
        System.out.println("Temp Path: " + getTempPath());

        // Create directories if they don't exist
        createDirectoryIfNotExists(getConfigPath());
        createDirectoryIfNotExists(getLogPath());
    }

    private static void createDirectoryIfNotExists(String path) {
        File dir = new File(path);
        if (!dir.exists()) {
            boolean created = dir.mkdirs();
            System.out.println("Created directory " + path + ": " + created);
        }
    }
}

Platform-Specific Configuration

import java.util.HashMap;
import java.util.Map;

public class PlatformSpecificConfig {
    public static class PlatformConfig {
        private String fileSeparator;
        private String pathSeparator;
        private String lineSeparator;
        private String tempDir;
        private String userHome;
        private String javaVersion;
        private String osName;

        public PlatformConfig() {
            this.fileSeparator = SystemUtils.FILE_SEPARATOR;
            this.pathSeparator = SystemUtils.PATH_SEPARATOR;
            this.lineSeparator = SystemUtils.LINE_SEPARATOR;
            this.tempDir = SystemUtils.JAVA_IO_TMPDIR;
            this.userHome = SystemUtils.USER_HOME;
            this.javaVersion = SystemUtils.JAVA_VERSION;
            this.osName = SystemUtils.OS_NAME;
        }

        @Override
        public String toString() {
            return String.format("PlatformConfig{fileSep='%s', pathSep='%s', lineSep='%s', tempDir='%s', userHome='%s', javaVersion='%s', osName='%s'}",
                fileSeparator, pathSeparator, lineSeparator, tempDir, userHome, javaVersion, osName);
        }
    }

    public static Map<String, String> getPlatformSpecificSettings() {
        Map<String, String> settings = new HashMap<>();

        // Common settings
        settings.put("java.version", SystemUtils.JAVA_VERSION);
        settings.put("java.vendor", SystemUtils.JAVA_VENDOR);
        settings.put("os.name", SystemUtils.OS_NAME);
        settings.put("os.version", SystemUtils.OS_VERSION);
        settings.put("os.arch", SystemUtils.OS_ARCH);

        // Platform-specific settings
        if (SystemUtils.IS_OS_WINDOWS) {
            settings.put("platform", "windows");
            settings.put("config.dir", SystemUtils.USER_HOME + "\\AppData\\Local\\MyApp");
            settings.put("log.dir", SystemUtils.USER_HOME + "\\AppData\\Local\\MyApp\\logs");
        } else if (SystemUtils.IS_OS_MAC) {
            settings.put("platform", "macos");
            settings.put("config.dir", SystemUtils.USER_HOME + "/Library/Application Support/MyApp");
            settings.put("log.dir", SystemUtils.USER_HOME + "/Library/Logs/MyApp");
        } else if (SystemUtils.IS_OS_LINUX) {
            settings.put("platform", "linux");
            settings.put("config.dir", SystemUtils.USER_HOME + "/.config/myapp");
            settings.put("log.dir", SystemUtils.USER_HOME + "/.local/share/myapp/logs");
        } else {
            settings.put("platform", "unknown");
            settings.put("config.dir", SystemUtils.USER_HOME + "/.myapp");
            settings.put("log.dir", SystemUtils.USER_HOME + "/.myapp/logs");
        }

        return settings;
    }

    public static void main(String[] args) {
        PlatformConfig config = new PlatformConfig();
        System.out.println("Platform Config: " + config);

        Map<String, String> settings = getPlatformSpecificSettings();
        System.out.println("Platform Settings:");
        settings.forEach((key, value) -> System.out.println("  " + key + " = " + value));
    }
}

System Information Logger

import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;

public class SystemInfoLogger {
    public static void logSystemInfo(String logFile) {
        try (PrintWriter writer = new PrintWriter(new FileWriter(logFile, true))) {
            LocalDateTime now = LocalDateTime.now();
            String timestamp = now.format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));

            writer.println("=== System Information Log - " + timestamp + " ===");
            writer.println("Operating System: " + SystemUtils.OS_NAME + " " + SystemUtils.OS_VERSION);
            writer.println("Architecture: " + SystemUtils.OS_ARCH);
            writer.println("Java Version: " + SystemUtils.JAVA_VERSION);
            writer.println("Java Vendor: " + SystemUtils.JAVA_VENDOR);
            writer.println("Java Home: " + SystemUtils.JAVA_HOME);
            writer.println("User Name: " + SystemUtils.USER_NAME);
            writer.println("User Home: " + SystemUtils.USER_HOME);
            writer.println("User Directory: " + SystemUtils.USER_DIR);
            writer.println("Temp Directory: " + SystemUtils.JAVA_IO_TMPDIR);
            writer.println("File Separator: " + SystemUtils.FILE_SEPARATOR);
            writer.println("Path Separator: " + SystemUtils.PATH_SEPARATOR);
            writer.println("Line Separator: " + SystemUtils.LINE_SEPARATOR);

            // Platform-specific information
            writer.println("Is Windows: " + SystemUtils.IS_OS_WINDOWS);
            writer.println("Is Linux: " + SystemUtils.IS_OS_LINUX);
            writer.println("Is macOS: " + SystemUtils.IS_OS_MAC);
            writer.println("Is Unix: " + SystemUtils.IS_OS_UNIX);

            writer.println("=== End System Information ===");
            writer.println();

        } catch (IOException e) {
            System.err.println("Error writing system info log: " + e.getMessage());
        }
    }

    public static void main(String[] args) {
        String logFile = SystemUtils.USER_HOME + SystemUtils.FILE_SEPARATOR + "system_info.log";
        logSystemInfo(logFile);
        System.out.println("System information logged to: " + logFile);
    }
}

Environment Detection

public class EnvironmentDetection {
    public static String detectEnvironment() {
        if (SystemUtils.IS_OS_WINDOWS) {
            return "Windows";
        } else if (SystemUtils.IS_OS_MAC) {
            return "macOS";
        } else if (SystemUtils.IS_OS_LINUX) {
            return "Linux";
        } else if (SystemUtils.IS_OS_UNIX) {
            return "Unix";
        } else {
            return "Unknown";
        }
    }

    public static boolean isDevelopmentEnvironment() {
        String userDir = SystemUtils.USER_DIR;
        return userDir.contains("development") ||
               userDir.contains("dev") ||
               userDir.contains("workspace") ||
               userDir.contains("projects");
    }

    public static boolean isProductionEnvironment() {
        String userDir = SystemUtils.USER_DIR;
        return userDir.contains("production") ||
               userDir.contains("prod") ||
               userDir.contains("live") ||
               userDir.contains("deploy");
    }

    public static String getJavaVersionCategory() {
        String version = SystemUtils.JAVA_VERSION;
        if (version.startsWith("1.8")) {
            return "Java 8";
        } else if (version.startsWith("9") || version.startsWith("10") || version.startsWith("11")) {
            return "Java 9-11";
        } else if (version.startsWith("12") || version.startsWith("13") || version.startsWith("14") || version.startsWith("15")) {
            return "Java 12-15";
        } else if (version.startsWith("16") || version.startsWith("17") || version.startsWith("18") || version.startsWith("19")) {
            return "Java 16-19";
        } else if (version.startsWith("20") || version.startsWith("21") || version.startsWith("22")) {
            return "Java 20+";
        } else {
            return "Unknown Java Version";
        }
    }

    public static void main(String[] args) {
        System.out.println("Environment: " + detectEnvironment());
        System.out.println("Is Development: " + isDevelopmentEnvironment());
        System.out.println("Is Production: " + isProductionEnvironment());
        System.out.println("Java Version Category: " + getJavaVersionCategory());
    }
}

Performance and Memory Information

System Resources

public class SystemResources {
    public static void printSystemResources() {
        Runtime runtime = Runtime.getRuntime();

        System.out.println("=== System Resources ===");
        System.out.println("Available Processors: " + runtime.availableProcessors());
        System.out.println("Total Memory: " + formatBytes(runtime.totalMemory()));
        System.out.println("Free Memory: " + formatBytes(runtime.freeMemory()));
        System.out.println("Used Memory: " + formatBytes(runtime.totalMemory() - runtime.freeMemory()));
        System.out.println("Max Memory: " + formatBytes(runtime.maxMemory()));

        // Memory usage percentage
        long usedMemory = runtime.totalMemory() - runtime.freeMemory();
        double memoryUsagePercent = (double) usedMemory / runtime.totalMemory() * 100;
        System.out.println("Memory Usage: " + String.format("%.2f", memoryUsagePercent) + "%");

        // System properties
        System.out.println("Java Version: " + SystemUtils.JAVA_VERSION);
        System.out.println("OS Name: " + SystemUtils.OS_NAME);
        System.out.println("OS Version: " + SystemUtils.OS_VERSION);
        System.out.println("OS Architecture: " + SystemUtils.OS_ARCH);
    }

    private static String formatBytes(long bytes) {
        if (bytes < 1024) return bytes + " B";
        int exp = (int) (Math.log(bytes) / Math.log(1024));
        String pre = "KMGTPE".charAt(exp-1) + "";
        return String.format("%.1f %sB", bytes / Math.pow(1024, exp), pre);
    }

    public static void main(String[] args) {
        printSystemResources();
    }
}

Best Practices

Guidelines for System Utilities

public class BestPractices {
    public static void main(String[] args) {
        // 1. Always check for platform-specific behavior
        String configPath = getPlatformSpecificConfigPath();
        System.out.println("Config Path: " + configPath);

        // 2. Use appropriate file separators
        String filePath = buildPath("config", "app.properties");
        System.out.println("File Path: " + filePath);

        // 3. Handle different line separators
        String multiLineText = buildMultiLineText();
        System.out.println("Multi-line text: " + multiLineText);

        // 4. Check Java version compatibility
        boolean isCompatible = checkJavaVersionCompatibility();
        System.out.println("Java Version Compatible: " + isCompatible);
    }

    public static String getPlatformSpecificConfigPath() {
        if (SystemUtils.IS_OS_WINDOWS) {
            return SystemUtils.USER_HOME + "\\AppData\\Local\\MyApp";
        } else if (SystemUtils.IS_OS_MAC) {
            return SystemUtils.USER_HOME + "/Library/Application Support/MyApp";
        } else {
            return SystemUtils.USER_HOME + "/.config/myapp";
        }
    }

    public static String buildPath(String... parts) {
        return String.join(SystemUtils.FILE_SEPARATOR, parts);
    }

    public static String buildMultiLineText() {
        return "Line 1" + SystemUtils.LINE_SEPARATOR +
               "Line 2" + SystemUtils.LINE_SEPARATOR +
               "Line 3";
    }

    public static boolean checkJavaVersionCompatibility() {
        String version = SystemUtils.JAVA_VERSION;
        // Check if Java version is 8 or higher
        return version.startsWith("1.8") ||
               Integer.parseInt(version.split("\\.")[0]) >= 9;
    }
}

Common Pitfalls

Avoiding Common Mistakes

public class CommonPitfalls {
    public static void main(String[] args) {
        // Pitfall 1: Hard-coding file separators
        String badPath = "C:\\Users\\username\\config"; // Windows only
        String goodPath = SystemUtils.USER_HOME + SystemUtils.FILE_SEPARATOR + "config";

        System.out.println("Bad path (Windows only): " + badPath);
        System.out.println("Good path (cross-platform): " + goodPath);

        // Pitfall 2: Not checking OS before using OS-specific features
        if (SystemUtils.IS_OS_WINDOWS) {
            // Use Windows-specific code
            System.out.println("Using Windows-specific features");
        } else if (SystemUtils.IS_OS_MAC) {
            // Use macOS-specific code
            System.out.println("Using macOS-specific features");
        } else {
            // Use Unix/Linux-specific code
            System.out.println("Using Unix/Linux-specific features");
        }

        // Pitfall 3: Not considering Java version compatibility
        String javaVersion = SystemUtils.JAVA_VERSION;
        if (javaVersion.startsWith("1.8")) {
            System.out.println("Using Java 8 compatible code");
        } else {
            System.out.println("Using modern Java features");
        }

        // Pitfall 4: Not handling different line separators
        String windowsText = "Line 1\r\nLine 2";
        String unixText = "Line 1\nLine 2";
        String macText = "Line 1\rLine 2";

        System.out.println("Current line separator: " + SystemUtils.LINE_SEPARATOR);
        System.out.println("Use SystemUtils.LINE_SEPARATOR for consistency");
    }
}

Conclusion

SystemUtils from Apache Commons Lang provides a robust set of utilities that make system operations more convenient, cross-platform, and powerful. By understanding these methods and their proper usage, you can write cleaner, more maintainable code that works across different platforms.

The key benefits include: