<![CDATA[Boot Camp Java - Medium]]> https://medium.com/boot-camp-java?source=rss----8ae4340d85e1---4 https://cdn-images-1.medium.com/proxy/1*TGH72Nnw24QL3iV9IOm4VA.png Boot Camp Java - Medium https://medium.com/boot-camp-java?source=rss----8ae4340d85e1---4 Medium Thu, 05 Nov 2026 15:42:39 GMT <![CDATA[Spring Boot 4.2: 15 Things That Change When You Upgrade From 4.1,]]>

RestTemplate deprecated, the AMQP starter repurposed, relative redirects, one forwarded header dropped. Each run on 4.1.2 vs 4.2.0-RC1.

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]]> https://medium.com/boot-camp-java/spring-boot-4-2-15-things-that-change-when-you-upgrade-from-4-1-f31bb777caf7?source=rss----8ae4340d85e1---4 https://medium.com/p/f31bb777caf7 Thu, 05 Nov 2026 12:17:55 GMT 2026-11-05T12:17:55.811Z <![CDATA[Split Brain Explained: What Happens When Two Nodes Both Think They Are the Leader]]>

A 4-second GC pause made a second leader in 5 of 5 runs and 50 emails went out twice. Why leases can’t stop it, and the 2 things that do.

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]]> https://medium.com/boot-camp-java/split-brain-explained-what-happens-when-two-nodes-both-think-they-are-the-leader-991ca420ba0c?source=rss----8ae4340d85e1---4 https://medium.com/p/991ca420ba0c Tue, 03 Nov 2026 11:17:50 GMT 2026-11-03T11:17:50.635Z <![CDATA[20 Array and String Interview Problems in Java, Solved by the 5 Patterns Behind Them]]>

Two pointers, sliding window, prefix sums, binary search: 20 problems, all tested. Fruit Into Baskets brute force: 34.9 s; the window: 1…

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]]> https://medium.com/boot-camp-java/20-array-and-string-interview-problems-in-java-solved-by-the-5-patterns-behind-them-061c2ed330f7?source=rss----8ae4340d85e1---4 https://medium.com/p/061c2ed330f7 Sun, 01 Nov 2026 06:21:31 GMT 2026-11-01T06:21:31.698Z <![CDATA[10 Java Traps That Fail a Correct-Looking DSA Solution, Tested on Java 25]]>

Negative modulo, a midpoint that overflows, Integer == above 127: ten Java traps that pass the sample test and fail the hidden one, all…

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]]> https://medium.com/boot-camp-java/10-java-traps-that-fail-a-correct-looking-dsa-solution-tested-on-java-25-b01f65161355?source=rss----8ae4340d85e1---4 https://medium.com/p/b01f65161355 Sat, 31 Oct 2026 10:03:01 GMT 2026-10-31T10:03:01.513Z <![CDATA[Spring Boot 4 + Java 25: 10 Things You Should Stop Doing in Your Spring Security Config]]>

@PreAuthorize without @EnableMethodSecurity let a plain user through. permitAll() in the wrong place opened /admin. 10 habits, tested.

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]]> https://medium.com/boot-camp-java/spring-boot-4-java-25-10-things-you-should-stop-doing-in-your-spring-security-config-97d3b38fda0b?source=rss----8ae4340d85e1---4 https://medium.com/p/97d3b38fda0b Fri, 30 Oct 2026 11:54:16 GMT 2026-10-30T11:54:16.597Z <![CDATA[Spring Boot 4 + Java 25: 10 Things You Should Stop Doing in Your Exception Handling]]>

A catch (Exception e) made shutdown take 5 seconds instead of 0. Returning e.getMessage() leaked the SQL and a customer’s email. A return…

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]]> https://medium.com/boot-camp-java/spring-boot-4-java-25-10-things-you-should-stop-doing-in-your-exception-handling-adcb0a5145a9?source=rss----8ae4340d85e1---4 https://medium.com/p/adcb0a5145a9 Wed, 28 Oct 2026 02:31:59 GMT 2026-10-28T02:32:00.388Z <![CDATA[Advent of Code in Java 25: 10 Language Features That Make Puzzle Solutions Shorter]]>

No class, no static main, sliding windows in one call, a parser the compiler checks, and the computeIfAbsent memo trap. Run on Java 25.

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]]> https://medium.com/boot-camp-java/advent-of-code-in-java-25-10-language-features-that-make-puzzle-solutions-shorter-ea05077e2efe?source=rss----8ae4340d85e1---4 https://medium.com/p/ea05077e2efe Tue, 27 Oct 2026 04:02:23 GMT 2026-10-27T04:02:23.695Z <![CDATA[15 Spring Boot 4 Features That Feel Like Easter Eggs, Each One Run and Verified]]>

A readiness switch that returns 503, exit code 42 for batch jobs, and a virtual-thread app that exits after one tick. 15 hidden features.

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]]> https://medium.com/boot-camp-java/15-spring-boot-4-features-that-feel-like-easter-eggs-each-one-run-and-verified-d1400d941c57?source=rss----8ae4340d85e1---4 https://medium.com/p/d1400d941c57 Mon, 26 Oct 2026 06:46:24 GMT 2026-10-26T06:46:24.566Z <![CDATA[Spring Boot 4 + Java 25: 10 Things You Should Stop Doing With @Transactional]]>

A checked exception committed the row, a caught one rolled everything back, and a rolled-back order still sent its email. 10 traps, tested.

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]]> https://medium.com/boot-camp-java/spring-boot-4-java-25-10-things-you-should-stop-doing-with-transactional-98c82d5cc242?source=rss----8ae4340d85e1---4 https://medium.com/p/98c82d5cc242 Sat, 24 Oct 2026 03:39:24 GMT 2026-10-24T03:39:24.842Z <![CDATA[Your Spring Boot 4 API Works Until Someone Asks for 5 Million Rows: 8 Limits, Measured]]>

findAll() on 5M rows hit OutOfMemoryError in 8.9 s on 512 MB; streaming peaked at 78 MB. 8 limits that stop unbounded work, each tested.

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]]> https://medium.com/boot-camp-java/your-spring-boot-4-api-works-until-someone-asks-for-5-million-rows-8-limits-measured-fd0f8c46a562?source=rss----8ae4340d85e1---4 https://medium.com/p/fd0f8c46a562 Wed, 21 Oct 2026 12:55:18 GMT 2026-10-21T12:55:19.485Z