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1. Introduction1.1. Course Structure1.2. Learning Goals1.3. Course Lecturers1.4. Topics1.5. Bibliography1.6. Tools1.7. Evaluation1.8. Agreements
2. Course Project2.1. Scope2.2. Rules of the Game2.3. Important Dates2.4. Requirements2.5. Tips
3. Git 1013.1. Introduction3.2. Installing Git3.3. Basic shell commands3.4. Git commands3.5. Ignoring files3.6. Branches3.7. Remote repositories
4. How Java Works4.1. Introduction4.2. Java Architecture4.3. Variables and Parameters4.4. Java Memory Model
5. Exception Handling5.1. Introduction5.2. Exception Types5.3. Declaring Exceptions Thrown by Methods5.4. Throwing Exceptions5.5. Custom Exceptions5.6. Accessing the Stack Trace
6. Inheritance6.1. Introduction6.2. Interfaces6.3. Method Overriding6.4. Multiple Inheritance6.5. Abstract Classes6.6. Method Overloading6.7. Polymorphism6.8. The Object Class6.9. Casting
7. Generic Programming7.1. Introduction7.2. Generic Methods7.3. Bounded and Unbounded Type Parameters7.4. Generic Types
8. Arrays8.1. One Dimensional Arrays8.2. Multidimensional Arrays8.3. The Arrays class8.4. Varags8.5. Limitations
9. Java Collections Framework9.1. Introduction9.2. The Collection Interface9.3. Lists9.4. Sets9.5. Queues9.6. The Collections Class9.7. Maps9.8. Choosing My Collection
10. Lambda Expressions10.1. Introduction10.2. What is a Lambda Expression?10.3. Functional Interfaces10.4. Local Variables in Lambda Expressions10.5. Standard Functional Interfaces10.6. Sorting with Lambdas
11. Streams11.1. Introduction11.2. Pipelines11.3. IntStream11.4. Optionals11.5. Operations
12. Maven12.1. Introduction12.2. Compiling Java12.3. Getting Started12.4. Coordinates12.5. Repositories12.6. Project Object Model12.7. Dependencies12.8. Standard Directory Layout12.9. Lifecycles and Phases12.10. Wrapper12.11. Archetypes12.12. Maven and Git12.13. Common Maven plugins
13. Testing13.1. Introduction13.2. Getting Started with JUnit 513.3. Basics of JUnit 513.4. JUnit Lifecycle API13.5. Expected Exceptions13.6. Timeouts13.7. Nested Tests13.8. Repeating Tests13.9. Third-party Assertion Libraries13.10. FIRST Properties of Good Tests13.11. What to Test: The Right-BICEP13.12. Boundary Conditions: The CORRECT Way
14. Regular Expressions14.1. String Manipulation14.2. Writing Regular Expressions14.3. Using Regular Expressions in String Methods14.4. Regex API
15. Design Patterns15.1. Instructions15.2. What is a Design Pattern?15.3. Gang of Four Design Patterns
16. I/O16.1. File manipulation16.2. I/O Streams16.3. Reading: FileReader and BufferedReader16.4. Reading: Scanner16.5. Reading: Files16.6. Writing Text Files
17. Serialization17.1. Introduction17.2. CSV17.3. JSON17.4. Reading and writing JSON with Jackson17.5. Binary serialization
18. Multithreading18.1. Concurrency18.2. Processes & Threads18.3. Multithreading in Java18.4. Thread Synchronization18.5. Thread Signaling
4. How Java Works
Programming Project 2022/23

4.4. Java Memory Model

JVM's Memory Area

jvm architecture

Image source

The stack

Each thread running in the Java virtual machine has its own thread stack, which contains information about which methods the thread has called (the call stack).

It also contains all the local variables and parameters.

Primitive local variables are stored on the thread stack.

Reference local variables point to objects in the heap.

The heap

The heap contains all objects created in your Java application, regardless of which thread created the object.

It does not matter if an object was created and assigned to a local variable, or created as a member variable of another object, it will be stored on the heap.

If an object is not referenced by any reference variable, it becomes garbage!

From time to time, the JVM will trigger the garbage collector to remove these unused objects from memory.

Demo

Here is a step-by-step demo video of how the stack and the heap are used when executing a Java program.

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