Exception Propagation

EXCEPTION PROPAGATION

Uncaught exceptions are propagated in the call stack until stack becomes empty, this propagation is called Exception Propagation.

After a method throws an exception, the runtime system searches the call stack for a method that contains a block of code(exception handler) that can handle the exception. The search begins with the method in which the error occurred and proceeds through the call stack in the reverse order in which the methods were called. When an appropriate handler is found, the runtime system passes the exception to the handler. Also, there's a note-worthy point:

For example:

Lets say, we have three methods m3(), m2() and m1(). Where  m3() calls in m2(), and m2() calls in m1(). So when

1) An exception occurs in the m3() and m3() don’t have any exception handler.

2) Uncaught exception will be propagated downward in stack i.e it will check appropriate exception handler in the m2().

3) Again in m2() if we don’t have any exception handler then again exception is propagated downward to m1() where it finds exception handler.

Program example in Java:

class EP{

void m3(){

int result = 100 / 0;  //Exception Generated

}

void m2()

{

method3();

}

void m1()

{

try

{

m2();

} 

catch(Exception e)

{

System.out.println("Exception is handled here");

}

}

public static void main(String args[]){

EP obj=new EP();

obj.m1();

System.out.println("Continue with Normal Flow...");

}

Principles of Programming Languages:

EasyExamNotes.com covered following topics in PPL.

• Language Evaluation Criteria
• Influences on Language Design 
• Language Categories
• Programming Paradigms
• Compilation
• Virtual Machines 
• Programming Environments
• Issues in Language Translation
• Parse Tree 
• Pointer and Reference type
• Concept of Binding
• Type Checking
• Strong typing 
• Sequence control with Expression
• Exception Handling 
• Subprograms
• Fundamentals of sub-programs
• Scope and lifetime of variable
• Static and dynamic scope
• Design issues of subprogram and operations
• Local referencing environments
• Parameter passing methods
• Overloaded sub-programs
• Generic sub-programs 
• Design issues for functions 
• Co routines 
• Abstract Data types
• Abstraction and encapsulation
• Static and Stack-Based Storage management
• Garbage Collection
• OOP in C++
• OOP in Java 
• OOP in C# 
• OOP in PHP
• Concurrency
• Semaphores 
• Monitors
• Message passing
• Java threads 
• C# threads 
• Exception handling 
• Exceptions
• Exception Propagation 
• Exception handler in C++ 
• Exception handler in Java
• Introduction and overview of Logic programming
• Basic elements of Prolog
• Application of Logic programming
• Functional programming languages
• Introduction to 4GL 

Practicals:

• Memory Implementation of 2D Array. 
• Memory Implementation of 3D Array. 
• Implementation of pointers in C++. 
• Write a program in Java to implement exception handling.
• Write a program in C++ to implement call by value parameter passing Method.
• Write a program in C++ to implement call by reference parameter passing Method. 
• Write a program in Java to implement concurrent execution of a job using threads.
• Implement Inheritance in C#.
• Implement Encapsulation in C#.
• Implement static/compiletime Polymorphism in C#.
• Implement dynamic/runtime Polymorphism in C#.

Previous years solved papers:

• PPL|RGPV|May 2018 
• PPL|RGPV|June 2017 

A list of Video lectures

• Click here

References:

1. Sebesta,”Concept of programming Language”, Pearson Edu 
2. Louden, “Programming Languages: Principles & Practices” , Cengage Learning 
3. Tucker, “Programming Languages: Principles and paradigms “, Tata McGraw –Hill. 
4. E Horowitz, "Programming Languages", 2nd Edition, Addison Wesley