Do
Don't
Iterating through collections
for (String item : items) {
	...
}
			
for (int i = 0; i < items.size(); i++) {
	String item = items.get(i);
	...
}
			
Iterator<String> iterator = items.getIterator();
while (iterator.hasNext()) {
	String item = iterator.next();
	...
}
Iteration through maps
for (String value : mapOfValues.values()) {
	...
}
			
for (String key : mapOfValues.keySet()) {
	...
}
			
for (Map.Entry<String, String> entry : mapOfValues.entrySet()) {
	String key = entry.getKey();
	String value = entry.getValue();
	...
}
			
for (String key : mapOfValues.keySet()) {
	String value = mapOfValues.get(key);
	...
}
Names of variables
String nameDescribingTheContent = service.getContent();
			
String s = service.getContent();
Defining variables
String nameDescribingTheContent = service.getContent();
...
String nameDescribingSomethingElse = service.getSomethingElse();
			
String s = null;
...
s = service.getContent();
...
s = service.getSomethingElse();
Initialization of variables
List<Something> listOfSomething = new ArrayList<Something>;
for (...) {
	...
	listOfSomething.add(something);
}
			
for (...) {
	List<Something> onlyInsideLoop = new ArrayList<Something>;
	...
}
			
List<Something> listOfSomething = null;
...
for (...) {
	...
	if (listOfSomething == null) {
		listOfSomething = new ArrayList<Something>;
	}
	listOfSomething.add(something);
}
			
List<Something> onlyInsideLoop = null;
...
for (...) {
	onlyInsideLoop = new ArrayList<Something>;
	...
}
Exception handling
try {
	// A few lines doing something specific
	...
} catch (SpecificException e) {
	// Handling the one or two things that you actually
	// can do something about
	...
}
			
try {
	... lots of lines ...
} catch (Exception e) {
	// Probably something exceptionally complex
	...
}
			
try {
	...
} catch (Exception e) {
	// Nothing
}
			
try {
	...
} catch (Throwable t) {
	// What the fuck do you think you are doing?
	...
}
Doing SQL queries
try (PreparedStatement statment = connection.prepareStatment(sql)) {
	...
} catch (SQLException e) {
	// Either retry or just log the error or don't catch at all
	...
}
			
PreparedStatement statment = null;
try {
	statment = connection.prepareStatment(sql);
	...
} catch (SQLException e) {
	...
} finally {
	if (statment != null) {
		statment.close();
	}
}
Using streams and other things that need to be closed
Path filePath = Paths.get("SomeFile.txt");
try (InputStream inputStream = Files.newInputStream(filePath)) {
	...
}
			
InputStream inputStream = ...
...
if (inputStream != null) {
	inputStream.close();
}
Getting results from within a loop
private boolean checkForSomeCondition(...) {
	for (...) {
		...
		if (someCondition) {
			return true;
		}
	}
	return false;
}
			
try {
	for (...) {
		...
		if (someCondition) {
			throw new SomeException();
		}
	}
} catch (SomeException exception) {
	// Maybe do something with the exception, maybe not
}
Implementing Comparables
public class AnObject implements Comparable {
	@Override
	public int compareTo(AnObject other) {
		return Integer.compare(id, other.getId());
	}
}			
			
@SuppressWarnings("rawtypes")
public class AnObject implements Comparable {
	@Override
	public int compareTo(Object arg0) {
		AnObject anObject = (AnObject) arg0;
		...
	}
}
			
public int compareTo(AnObject other) {
	return Integer.valueOf(this.id).compareTo(Integer.valueOf(other.getId()));
}