Comparison

Re vs Java SE 21 Developer

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Re

Features
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繰り返すほど、知識は武器になる。ネットワークスペシャリスト試験の午前対策アプリ。 考えるより解く。それがRe:Pra(リプラ)スタイル。 本アプリは、「とにかく速く」「何度も繰り返す」ことで記憶を強化する、過去問特化型の反復練習アプリです。 ------- 【こんなあなたにおすすめ】 • 一問一答でテンポよく学びたい • 解説より、手を動かして覚えたい • キーワードを見てパターンで解けるようになりたい Re:Praはあえて解説を省き、「問題文と選択肢の感覚的な理解」に特化。 思考より反復、読解より直感。そんな学習があってもいい。 ------- 【主な機能】 • 過去問を“素早く何度も”繰り返す • 正解するまで次の問題には進まない • 間違えた問題だけを出題する「苦手克服モード」 • 自分で印をつけて復習できる「要チェック機能」 • 問題ごとに直近5回分の正誤履歴を表示 ------- 本アプリは、定期的にサードパーティ広告が流れます。運営のためご容赦ください。 また、広告を流すためにデバイスID、使用状況を取得していますが、 個人情報等は一切取得しておりませんので、安心してご利用ください。 なお、広告はアプリ内課金で非表示にすることもできますので、 本アプリを気に入っていただけましたら、ご検討ください。

About

Java SE 21 Developer

Features
Read full description

Keep studying across your phone, tablet and desktop. Use your phone on the move and a tablet or desktop when you want more room to study. Connect the same StudyCert account to continue your learning in the app and on the desktop web. Prepare for Oracle Java SE 21 / 1Z0-830 with 500 practice questions and 149 key terms. Study coverage · 10 areas • Handling Date, Time, Text, Numeric and Boolean Values • Controlling Program Flow • Using Object-Oriented Concepts in Java • Handling Exceptions • Working with Arrays and Collections • Working with Streams and Lambda expressions • Packaging and Deploying Java Code • Managing Concurrent Code Execution • Using Java I/O API • Implementing Localization 1. Build your foundation with key terms Use flashcards to learn meanings, exam context and selection cues. Mark terms as known or not yet known, then revisit unstudied or unfamiliar cards. Edit card content to suit your learning and restore the original when needed. 2. Practice and understand each answer Study in 50-question sets, by domain or by difficulty. Work through single- and multiple-choice questions, then read the explanation for the answer and each option. Choose all, unfinished or wrong questions; shuffle questions and choices; use a study timer; and resume where you left off. From the results of domain study, continue with key terms and related questions in the next domain. 3. Review mistakes and uncertain concepts Choose recent errors, review marks or repeated mistakes on the Review screen and practice them again. Check accuracy by domain alongside the terms you know or still need to learn. The glossary report shows term-learning status and accuracy on related questions together. 4. Check your preparation with a mock exam Practice time management with 50 questions in 120 minutes. Change answers before submission, resume a saved exam and receive grading when time expires. Afterwards, see correct, wrong and unanswered counts, your score and domain results, then revisit mistakes. This practice feature uses the included questions and does not determine an official exam score or pass result. Tools that fit your study routine Optional audio study reads terms and meanings aloud. Choose whether to include exam context and selection cues, set repeats and pauses, and control playback with the mini player. In the mobile app, audio can continue in the background and with the screen locked. A study calendar, learning streaks, weekly goals, reminders for unmet goals and light, dark or system themes support your routine. Learning records are managed for each supported language. Some features require paid access. Check the included features and price on the purchase screen. Purchase restoration is supported. This is an independent study aid, not an official, affiliated or endorsed app of any exam administrator or certification body. Exam names and trademarks belong to their respective owners.

Screenshots

Re4 screens
Java SE 21 Developer4 screens

Verdict

The call

The clearest difference is ads: Java SE 21 Developer at none against Re's shown. Java SE 21 Developer also leads on iOS requirement (15.1 vs 17.6). On price, update cadence, in-app purchases and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Re sells 2 one-off in-app purchases and Java SE 21 Developer sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

UpkeepUpdate frequency

Re ships an update every 5 days, Java SE 21 Developer weekly. The most recent releases landed on October 30, 2026 and November 13, 2026 respectively.

Scorecard2 real differences · 4 level
Re versus Java SE 21 Developer: the parameters behind the verdict, then further details
ParameterReJava SE 21 Developer
PriceFreeFree
Update frequencyEvery 5 days — betterWeekly
AdsYesNo — better
In-app purchasesYesYes
DevicesiPhone, iPadiPhone, iPad, iPod — better
Requires iOS17.615.1 — better
Further details — not scored
Size18 MB233 MB
Age rating4+4+
DeveloperMendoxa LLCCHOI SEONGMIN

In-app purchases

2 purchases

Re

One-time2
  • Mendoくんパワーアップ(開発支援)$0.49
  • 広告非表示$0.99
1 purchases

Java SE 21 Developer

One-time1
  • Lifetime Access$4.99

Questions

Is Re free?
Re is free to download, with in-app purchases available.
Is Java SE 21 Developer free?
Java SE 21 Developer is free to download, with in-app purchases available.
Do Re or Java SE 21 Developer have ads?
Re shows ads; Java SE 21 Developer does not.
Which is updated more often, Re or Java SE 21 Developer?
Re ships an update every 5 days, and Java SE 21 Developer weekly. Most recently, Re was updated on October 30, 2026 and Java SE 21 Developer on November 13, 2026.

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