1. Basic knowledge necessary for Java architects
What is a memory leak in Java? How to avoid memory leaks?
A memory leak in Java means that after a program applies for memory, it cannot release unused memory space. Methods to avoid memory leaks include: avoiding the use of the finalize method, manually cleaning up objects that are no longer used when using cache, closing resources in a timely manner, etc.
What is polymorphism in Java? Please give an example.
Polymorphism in Java means that an interface or superclass can reference instances of multiple actual types. For example, a parent class reference can point to an object of a child class and can use the child class's methods and properties. This is achieved through method overriding and overloading.
What is exception handling in Java? Please briefly explain the exception handling mechanism in Java.
Exception handling in Java is a mechanism for handling abnormal situations in a program. When an exception occurs in the program, Java will throw an exception object, which the program can catch and handle. Methods for handling exceptions include try-catch statement blocks and finally statement blocks.
Please explain the reflection mechanism in Java and its application scenarios.
The reflection mechanism in Java means that the program can check information about classes, methods, properties, etc. at runtime, and can create objects, call methods, set properties, etc. at runtime. Reflection mechanism is often used in framework design, unit testing, plug-in mechanism, etc.
Please explain the MVC pattern in Java and its application scenarios.
The MVC pattern refers to dividing the program into three parts: Model, View and Controller. The model is responsible for processing data and business logic, the view is responsible for displaying data and interfaces, and the controller is responsible for receiving user input and calling the model for processing, and then passing the results to the view for display. MVC pattern is commonly used in web applications