Exception Best Practices

Following exception handling best practices makes your code more robust and maintainable. Learn when to catch vs propagate, how to log properly, and common anti-patterns to avoid.

30 min•By Priygop Team•Last updated: Feb 2026

Best Practices for Exception Handling

Catch specific exceptions first, then general ones — catch (IOException e) before catch (Exception e)
Never catch Exception or Throwable silently — always log or rethrow, never empty catch blocks
Use try-with-resources for AutoCloseable objects (files, connections, streams)
Don't use exceptions for control flow — they're expensive; use if-else for expected conditions
Include meaningful messages in exceptions — describe what went wrong and what was expected
Log at the right level — severe errors vs warnings vs info vs debug
Document exceptions with @throws in JavaDoc to help callers know what to expect

Try It Yourself: Robust Data Processor

Try It Yourself: Robust Data ProcessorJava

Java Editor

✓ ValidTab = 2 spaces

public class DataProcessor {
    // Best practice: specific exception messages
    static double[] parseNumbers(String[] inputs) {
        double[] results = new double[inputs.length];
        int validCount = 0;
        
        for (int i = 0; i < inputs.length; i++) {
            try {
                results[validCount] = Double.parseDouble(inputs[i].trim());
                validCount++;
            } catch (NumberFormatException e) {
                System.out.println("Skipping invalid: '" + inputs[i] + "'");
            } catch (NullPointerException e) {
                System.out.println("Skipping null at index " + i);
            }
        }
        
        double[] valid = new double[validCount];
        System.arraycopy(results, 0, valid, 0, validCount);
        return valid;
    }
    
    static void printStats(double[] data) {
        if (data.length == 0) {
            System.out.println("No valid data to process!");
            return;
        }
        
        double sum = 0, min = data[0], max = data[0];
        for (double d : data) {
            sum += d;
            if (d < min) min = d;
            if (d > max) max = d;
        }
        
        System.out.println("\n=== Statistics ===");
        System.out.println("Count: " + data.length);
        System.out.println("Sum: " + sum);
        System.out.println("Average: " + String.format("%.2f", sum / data.length));
        System.out.println("Min: " + min);
        System.out.println("Max: " + max);
    }
    
    public static void main(String[] args) {
        String[] rawData = {"42", "hello", "3.14", "100", "", "abc", "75.5", null, "88"};
        
        System.out.println("=== Processing Data ===");
        double[] clean = parseNumbers(rawData);
        printStats(clean);
    }
}

public class DataProcessor {
    // Best practice: specific exception messages
    static double[] parseNumbers(String[] inputs) {
        double[] results = new double[inputs.length];
        int validCount = 0;
        
        for (int i = 0; i < inputs.length; i++) {
            try {
                results[validCount] = Double.parseDouble(inputs[i].trim());
                validCount++;
            } catch (NumberFormatException e) {
                System.out.println("Skipping invalid: '" + inputs[i] + "'");
            } catch (NullPointerException e) {
                System.out.println("Skipping null at index " + i);
            }
        }
        
        double[] valid = new double[validCount];
        System.arraycopy(results, 0, valid, 0, validCount);
        return valid;
    }
    
    static void printStats(double[] data) {
        if (data.length == 0) {
            System.out.println("No valid data to process!");
            return;
        }
        
        double sum = 0, min = data[0], max = data[0];
        for (double d : data) {
            sum += d;
            if (d < min) min = d;
            if (d > max) max = d;
        }
        
        System.out.println("\n=== Statistics ===");
        System.out.println("Count: " + data.length);
        System.out.println("Sum: " + sum);
        System.out.println("Average: " + String.format("%.2f", sum / data.length));
        System.out.println("Min: " + min);
        System.out.println("Max: " + max);
    }
    
    public static void main(String[] args) {
        String[] rawData = {"42", "hello", "3.14", "100", "", "abc", "75.5", null, "88"};
        
        System.out.println("=== Processing Data ===");
        double[] clean = parseNumbers(rawData);
        printStats(clean);
    }
}

Output

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Java|51 lines|1791 chars|✓ Valid syntax

UTF-8

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