Java - Recommended GC log options for Java 8 and Java 9
Java 8 -XX:+PrintGCDetails -XX:+PrintReferenceGC -XX:+PrintTenuringDistribution -Xloggc: -XX:+PrintGCTimeStamps Java 9 -Xlog:gc* ,gc+ref=debug ,gc+...
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Java - Garbage collectors
1. Serial -XX:+UseSerialGC JVM 2. Parallel default 3. CMS(Current Markup Sweep) -XX:+USeParNewGC 4. G1 –XX:+UseG1GC Note: Java8 and G1 collector can optimize...
Java - ZonedDateTime formatter for ISO-8601
Parse example 1 2 3 4 5 6 7 DateTimeFormatterBuilder builder = new DateTimeFormatterBuilder(); DateTimeFormatter formatter = builder .parseCaseInsens...
Java - heap dump utilities
Heap histogram 1 jmap -histo [pid] Heap usage 1 jmap -heap [pid]
Java - an example code to extract mime type from base64 string of an image
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 private boolean isMatch(byte[] pattern,...