Legacy system modernization in Software Engineering - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Legacy System Risks

Which of the following is the most common risk associated with maintaining legacy systems?

A Easier integration with modern cloud services

B Improved system performance from older, stable code

C Lower maintenance costs because the system is well understood

D Increased security vulnerabilities due to outdated software components

💡 Hint

Think about how old software might not receive updates or patches.

Legacy systems often use outdated software components that no longer receive security updates, making them vulnerable to attacks.

🚀 Application

intermediate

Choosing Modernization Strategies

A company wants to update its legacy system without disrupting current operations. Which modernization approach best fits this goal?

A Encapsulation by wrapping legacy components with APIs

B Complete system rewrite from scratch

C Immediate replacement with a new off-the-shelf product

D Ignoring the legacy system and building a parallel system

💡 Hint

Consider approaches that allow old and new systems to work together.

Encapsulation wraps legacy components with APIs, enabling gradual modernization without disrupting existing operations.

🔍 Analysis

advanced

Analyzing Modernization Impact

What is a likely consequence of refactoring legacy code to improve modularity?

A Reduced need for testing after changes

B Decreased system flexibility and harder future updates

C Increased risk of introducing new bugs due to code changes

D Immediate elimination of all legacy system dependencies

💡 Hint

Think about what happens when you change old code.

Refactoring legacy code can introduce new bugs because the code is changed, even though it improves modularity and maintainability.

❓ Comparison

advanced

Comparing Modernization Techniques

Which statement correctly compares 'rehosting' and 'refactoring' in legacy system modernization?

A Rehosting moves the system to new infrastructure with minimal changes; refactoring changes code to improve design

B Rehosting involves changing code structure; refactoring moves the system to new hardware without code changes

C Both rehosting and refactoring require complete system rewrites

D Refactoring is faster and cheaper than rehosting because it avoids infrastructure changes

💡 Hint

Focus on what each technique changes: code or infrastructure.

Rehosting moves legacy systems to new infrastructure with minimal code changes, while refactoring changes the code to improve its design and maintainability.

❓ Reasoning

expert

Evaluating Modernization Outcomes

A legacy system modernization project used a 'strangler pattern' to gradually replace old components. After completion, what is the expected state of the system?

A The legacy system runs in parallel indefinitely with no new components added

B The legacy system is completely replaced by new components with no downtime during transition

C The legacy system is abandoned and all data is manually migrated to a new system at once

D The legacy system is rewritten entirely before any new components are introduced

💡 Hint

Consider how the strangler pattern replaces parts step-by-step.

The strangler pattern gradually replaces legacy components with new ones, allowing the system to be fully modernized without downtime.