Comparison

HTMLの教科書 vs Oracle 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

HTMLの教科書

Features
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■どんな人にでもわかりやすい『よくわかるHTMLの教科書』 ■むずかしいHTMLの基礎を小学生でも学べるように、どこよりもわかりやすく解説! プログラミングってむずかしい概念ばかりでですよね。 私も最初はプログラミングが苦手で、何度も学習を諦めてしまいそうになったことがあります。 とにかくわからないことがありすぎて、自分はなんてバカなんだ・・・。と落ち込むことばかり。 世にあるプログラミング学習教材は難しすぎる!プログラミングがある程度できるようになった今でも、私はそう思います。 いろんな学習教材を試しに使ってみても、難しい言葉やわからない専門用語だらけで意味がわかりません。 そこで! 私は誰でも理解できるような『よくわかるHTMLの教科書』を作ることにしました。 このアプリでは、誰でも!小学生でも!おばあちゃんでも! 本当に誰でも理解ができるぐらいわかりやすい表現を心がけて、HTMLを解説しています。 それが『よくわかるプログラミングの教科書』シリーズです。 今だけ期間限定で、300円で購入できるようになっておりますので、 プログラミングを学びたい方はぜひご購入ください。 *もしアプリ内でわからない箇所がありましたらお問い合わせフォームからご連絡ください。 すぐに表現を改善して、わかるようになるまでわかりやすい表現を考え直します。

About

Oracle Java SE 21 Developer

Features
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Prepare for Oracle Java SE 21 Developer with one connected flow from core concepts to practice, review, and mock exams. Official credential reference: Oracle Java SE 21 Developer Professional The current question bank contains 500 questions. Study in 50-question sets or focus by domain, subdomain, and difficulty. Single-select and multiple-select items are supported where applicable. Immediately after answering, check the correct-answer explanation and the reasoning for every choice so you understand both why the answer is correct and why the alternatives do not fit. Structured study and records • 50-question set learning plus domain, subdomain, and difficulty filters • Immediate grading, correct-answer explanations, and choice-by-choice rationales • Separate saved progress and resume for set, domain, and difficulty study and for mock exams • A study-history calendar with daily question and key-term activity, monthly totals, and study streaks • Review of wrong answers, repeated misses, review notes, and weak-area analysis • Timed mock exams that hide explanations until submission, allow answer changes before submission, and show results by domain • Weekly goal reminders with a configurable notification time • Light, dark, and system themes A smooth learning flow Move quickly among Home, Study, Review, Mock Exam, and Settings. Each mode keeps its own learning state, and moving to the next item after a long explanation automatically returns the new question card to the top. Basic terms and optional audio study Use the basic-term flashcards as the primary memorization tool. When useful, turn on automatic audio playback to repeat key terms while walking, resting, or preparing for sleep without continuously reading the screen. The questions in this app are current as of August 2026, and we plan to review and update every exam’s question bank at least once a year. The questions are independently authored for study and do not reproduce live exam items, dumps, leaked questions, or third-party question banks. This is an independent study app and is not affiliated with, endorsed by, or sponsored by any certification body, exam provider, or trademark owner. Exam names and trademarks belong to their respective owners.

Screenshots

HTMLの教科書4 screens
Oracle Java SE 21 Developer4 screens

Verdict

The call

The clearest difference is price: Oracle Java SE 21 Developer at Free against HTMLの教科書's $1.99. HTMLの教科書's advantage is in-app purchases (none vs 1). On ads, device support and iOS requirement 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

Oracle Java SE 21 Developer is free to download; HTMLの教科書 costs $1.99 up front. Oracle Java SE 21 Developer sells 1 one-off in-app purchase. HTMLの教科書 asks for nothing beyond the download.

Scorecard2 real differences · 4 level
HTMLの教科書 versus Oracle Java SE 21 Developer: the parameters behind the verdict, then further details
ParameterHTMLの教科書Oracle Java SE 21 Developer
Price$1.99Free — better
Update frequency—Every 4 days
AdsNoNo
In-app purchasesNo — betterYes
DevicesiPhone, iPodiPhone, iPad, iPod — better
Requires iOS15.115.1
Further details — not scored
Size21 MB201 MB
Age rating4+4+
DeveloperCreatopia Inc.CHOI SEONGMIN

In-app purchases

None

HTMLの教科書

No in-app purchases

1 purchases

Oracle Java SE 21 Developer

One-time1
  • Lifetime Access$4.99

Questions

Is HTMLの教科書 free?
HTMLの教科書 costs $1.99, with no in-app purchases.
Is Oracle Java SE 21 Developer free?
Oracle Java SE 21 Developer is free to download, with in-app purchases available.
Do HTMLの教科書 or Oracle Java SE 21 Developer have ads?
Neither HTMLの教科書 nor Oracle Java SE 21 Developer shows ads.

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