agustarc

public enum Singleton {
  INSTANCE;  
}

agustarc

public class Singleton {
  private Singleton() {}
  public static Singleton getInstance() {
    return LazyHolder.INSTANCE;
  }
  
  private static class LazyHolder {
    private static final Singleton INSTANCE = new Singleton();  
  }
}

agustarc

public class Singleton {
  private volatile static Singleton instance;
  private Singeton() {}
  
  public static Singleton getInstance() {
    if (instance == null)  {
        synchronized(Singleton.class) {
          if (instance == null) {
              instance == new Singleton();  
          }

agustarc

public class LeakActivity extends Activity {

  private final Handler handler = new Handler() {
    @Override
    public void handleMessage(Message msg) {
      // do work
    }
  }
  
  @Override

agustarc

public class NonLeakActivity extends Activity {
  private NonLeakHandler handler = new NonLeakHandler(this);
  
  private static final class NonLeakHandler extends Handler {
    private final WeakReference<NonLeakActivity> ref;
    
    public NonLeakHandler(NonLeakActivity act) {
      ref = new WeakReference<>(act);  
    }
    

agustarc

@AutoValue
public abstract class Product {
  @SerializedName("id")
  public abstract long getId();
  
  @SerializedName("name")
  public abstract String getName();
  
  @SerializedName("price")
  public abstract float getPrice();

agustarc

@GsonTypeAdapterFactory
public abstract class AutoValueGsonFactory implements TypeAdapterFactory {
  public static TypeAdapterFactory create() {
    return new AutoValueGson_AutoValueGsonFactory();  
  }
}

agustarc

@AutoValue
public abstract class Product {
  @SerializedName("id")
  public abstract long getId();
  
  @SerializedName("name")
  public abstract String getName();
  
  @SerializedName("price")
  public abstract float getPrice();

agustarc

@AutoValue
abstract class ProductBuilder {
    @SerializedName("id")
    abstract long getId();

    @SerializedName("name")
    abstract String getName();

    @SerializedName("price")
    abstract float getPrice();

agustarc

@Module
public class SampleModule {
  private static final int CONNECT_TIMEOUT = 15;
  private static final int WRITE_TIMEOUT = 15;
  private static final int READ_TIMEOUT = 15;
  private static final String baseUrl; // your base url;  
  
  @Provides
  @Singleton
  Cache provideOkHttpCache(Application application) {