In the Android code below, we will use a `DexClassLoader` which takes a parent `ClassLoader` in the constructor. If the parent cannot load the class, the child will try it.
It simply tells that when a class loader tries to load a class, it should first try to delegate the loading to its parent. The delegation scheme is a contract, often breached, of a `ClassLoader`. Each class is identified by its name and its class loader. `ClassLoader`s (should) follow the delegation scheme.Ģ. There are two things you still need to know for loading your code dynamically:ġ. In this post, we will use “class loading” for all the three phases together. This phase uses a special VM lock, one per class or interface, and is what makes singletons thread-safe (see Effective Java Item 3). Before executing though, the class needs to be initialized: this is where the VM runs static initializer blocks and set defaults values for the static fields. Linking takes the VM data structure, verifies it for errors, and merges it into the state of the VM, i.e. class file, for example in a jar or over the network, and reading its binary content in some VM data structure. Java part: Class loading basicsĬlass loading is actually split in three different phases: loading, linking and initializiation. This is called class loading and in Java it is performed by a `ClassLoader`. Every time some code access a class in some way, such as accessing one of its static fields or creating a new instance, if the accessed class is not loaded yet, the VM will load it and link it, so it can be used. Let’s start talking about how Java loads code. This post has actually two parts: a first part about Java class loading in general and a second part about our Android example. Along the way, we will explain how class loading works under the hood. In the code sample, we will fetch two dex files, load them dynamically, and then execute their code.
This technique is useful if you want to update parts of an app without rolling out a complete update. Make the connections that help your friends and strengthen your relationships.Today we are going to see how code can be downloaded and executed over the network.
Search through all the notes you’ve taken in one place. With the Dex Dashboard, organize your relationships with custom tags and views. Be more thoughtful in your next conversation. Dex makes it easy to remember important details. Remember the name of your coworker’s daughter? What about your friend's spouse?
Stay warm with your professional and personal network. Configure Dex to send you regular reminders: maintain relationships even when life gets busy. With one click, see your past notes, details, and reminders, Add Dex to Chrome to manage relationships from Facebook, LinkedIn, Messenger, Twitter, Gmail, and more! Easily visualize, organize, understand, and manage all your relationships for free.īy installing the extension, you agree to Dex's Terms of Service (/termsofservice) and Privacy Policy (/privacypolicy). Build stronger relationships with Dex.ĭex is a personal relationship manager that reminds you to keep in touch with people you would otherwise forget. Visualize, understand, and manage your relationships for free.