This post was migrated from Tistory. You can find the original here. Connecting to MongoDB // application.properties spring.data.mongodb.host= ~~ spring.data.mongodb.port=27017 spring.data.mong...

This post was migrated from Tistory. You can find the original here. Looking at it in terms of layers: JDBC (Java Database Connectivity): The API (interface) Java provides for accessing a datab...

This post was migrated from Tistory. You can find the original here. Deadlock Conditions for occurrence Mutual exclusion - A resource can only be used by one process at a time. Hold and ...

This post was migrated from Tistory. You can find the original here. Stack Memory This is the area where local variables and parameters related to function calls are stored. When a function is c...

This post was migrated from Tistory. You can find the original here. TCP/UDP Socket Protocol The Socket Interface lets you use the TCP and UDP communication protocols. The Socket Interface is ...

This post was migrated from Tistory. You can find the original here. Getting started Looking at messenger services today, there doesn’t seem to be much need for other tables to reference a Messa...

This post was migrated from Tistory. You can find the original here. Inner Join Extracts only the intersecting rows. (No NULLs.) Outer Join Left Outer Join Extracts based on...

This post was migrated from Tistory. You can find the original here. HTTP GET vs POST The answer to this question is mostly about “when to use which method” — that’s the main answer, and the dif...

This post was migrated from Tistory. You can find the original here. Factory Method Instead of creating a Product object directly, a Factory class creates the Product for you. There are multi...

This post was migrated from Tistory. You can find the original here. Kafka producer key CompletableFuture<SendResult<Integer, String>> future = kafkaTemplate.send(MSG_TOPIC, key,...