Programming VIP

Multithreading What is a process A process is an application What is a thread A thread is an execution scenario / progression unit in a process A process can start multiple threads For java program, when entering in DOS command window: After entering the java HelloWorld. The JVM will be started first, and the JVM is a process At the same tim ...

With the rise of micro service architecture, maintaining service security has become more challenging than before. Multiple back-end server instances using a single static key to access the database server will bring huge risks. If the key certificate is leaked, the whole system will be affected. In order to solve the impact of key certificate ...

Open Policy Agent (OPA) is an open source lightweight general policy engine, which can replace the built-in policy function module in the software to help users realize the decoupling of service and policy engine. Benefit from OPA Perfect ecosystem , users can easily integrate OPA and other services, such as program library, HTTP API, etc.As sh ...

Method area of jvm definition (1) The method area, like the java heap, is a memory area shared by all threads (2) The method area is created when the jvm starts, and its actual physical memory space can be discontinuous like the java heap area (3) The size of the method area, like the heap space, can be fixed or expanded (4) The size of the m ...

Today's test 1. Simply describe the storage of a variable x=10 in the heap area of the stack area in memory. Stack area: storage is the corresponding relationship between the variable name and the memory address, so it can be simply understood as: variable name is stored in the memory address heap area: it stores the variable value Emphasi ...

1. What is a business? Database transaction is simply to operate several different SQL statements as a whole, either all successful or all failed. It has four characteristics: atomicity, consistency, isolation and persistence. Spring transaction is a transaction processing mechanism encapsulated in database transaction. It has two manageme ...

Both the sleep method and the wait method are used to put the thread into the sleep state, and both the sleep method and the wait method can respond to the interrupt interrupt, that is, if the thread receives the interrupt signal during sleep, it can respond and throw the InterruptedException exception. What are the differences between sleep an ...

1, python open file: built in function open File operation: open (parameter 1, parameter 2, parameter 3) -- other parameters are generally not used. See the notes for details Parameter 1: specify file Parameter 2: open model r: Read a: Append write. If it does not exist, it will be automatically created w: Overwrite write. If it does not exist ...

Asynchronous orchestration Introduction to completable future Future is a class added in Java 5 to describe the results of an asynchronous calculation. You can use the isDone method to check whether the calculation is completed, or use get to block the calling thread until the calculation is completed and the result is returned. You can a ...

03_Java basic syntax The Scanner class cannot get the char type directly from the keyboard Process control Process control statements are statements used to control the execution order of statements in the program. Statements can be combined into small logic modules that can complete certain functions.Its process control mode adopts three b ...