Java Best Practices
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Code Readability & Naming
Clear, descriptive names for variables, methods, and classes make code self-documenting — calculateTotalPrice() communicates intent far better than a vaguely named calc().
Example: Code Readability & Naming
public class Main {
static double calculateTotalPrice(double price, double taxRate) { // descriptive name
return price + (price * taxRate);
}
public static void main(String[] args) {
System.out.println(calculateTotalPrice(100, 0.1));
}
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Avoid String Concatenation in Loops
Repeatedly concatenating strings with + inside a loop creates a new String object on every iteration since strings are immutable; use StringBuilder instead for efficient repeated appending.
Example: Avoid String Concatenation in Loops
public class Main {
public static void main(String[] args) {
StringBuilder sb = new StringBuilder(); // avoids repeated new String objects
for (int i = 0; i < 5; i++) {
sb.append(i);
}
System.out.println(sb);
}
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Defensive Null Checks
Checking for null before dereferencing a value you're not certain is populated — especially on data from user input, file reads, or external APIs — prevents the single most common runtime exception in Java, NullPointerException.
Example: Defensive Null Checks
public class Main {
public static void main(String[] args) {
String input = null;
if (input != null) {
System.out.println(input.length());
} else {
System.out.println("Input was null");
}
}
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Safe Resource Handling
Wrapping file handles, database connections, and other closeable resources in try-with-resources guarantees they're released even if an exception interrupts the operation midway.
Example: Safe Resource Handling
import java.io.FileWriter;
import java.io.IOException;
public class Main {
public static void main(String[] args) throws IOException {
try (FileWriter writer = new FileWriter("data.txt")) { // guaranteed release
writer.write("Hello");
}
}
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Code Reuse with Helper Methods
Extracting repeated logic into small, well-named helper methods keeps your code DRY (don't repeat yourself) and makes each piece independently testable rather than duplicated across multiple places.
Example: Code Reuse with Helper Methods
public class Main {
static int square(int n) { // reusable, testable in isolation
return n * n;
}
public static void main(String[] args) {
System.out.println(square(4));
System.out.println(square(5));
}
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