Evidence-based interview review

This score is calculated from the technical coverage, depth, examples, trade-offs, and submitted challenge—not answer length alone.

Completed September 24, 2026 · Java · 4–5 years · Backend Developer

Retry interview

Section scores

A balanced view across technical depth, delivery, and problem solving.

Core Java86

Spring Boot84

Microservices / Backend79

Problem Solving76

Coding81

Communication88

Strengths

Strong practical understanding of collections and stream operations
Explained service boundaries and asynchronous messaging clearly
Good working knowledge of Spring Boot dependency injection

Areas to improve

Make the JVM memory explanation more precise
Connect circuit breaker states to concrete production behavior
Call out empty-string and Unicode edge cases before coding

ANSWER REVIEW

Your answers compared with reference answers

2 reviewed

How does the JVM decide when an object can be garbage collected?

Score out of 100 · open to compare the evidence

Your actual answer

Objects that are no longer referenced are eligible for garbage collection.

What was missing

GC roots, reachability analysis, reference types, and the generational hypothesis.

Reference answer

Start from GC roots such as active thread stacks and static fields, then explain how unreachable object graphs become eligible for collection. Eligibility does not guarantee immediate collection.

What happens when a circuit breaker moves from open to half-open?

Score out of 100 · open to compare the evidence

Your actual answer

The circuit breaker blocks calls while the downstream service is failing, then checks whether it has recovered.

What was missing

A limited number of trial calls and the transition back to closed or open based on their outcome.

Reference answer

After the wait duration, the breaker permits a small number of probe requests. Successful probes close it; failures reopen it and restart the wait window.

Challenge and code review

First non-repeating character

Correctness

Passed the primary and duplicate-character cases.

Complexity / plan

O(n) time and O(k) additional space using insertion-ordered counts.

Code quality

Clear method boundary and readable naming. The two-pass approach was easy to verify.

Edge cases

Add explicit handling for null, empty strings, and supplementary Unicode characters.

Explanation

The approach was explained accurately, with a good trade-off discussion.

Your submitted code

Map<Character, Integer> counts = new LinkedHashMap<>(); // candidate solution

Reference solution

Count characters in insertion order, then return the first entry whose count is one.

NEXT PRACTICE

Turn gaps into a focused study plan.

JVM memory modelGarbage collection rootsResilience4j circuit breakersUnicode-safe string handling

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