core apis and exceptions

the standard library you use every day, and how errors move through a program.

1. 01the string apiStringBuilder, formatting, compact strings and the methods worth knowing.
2. 02wrappers and autoboxingint vs Integer, the integer cache, and why 127 == 127 but 128 != 128.
3. 03math and random numbersMath, StrictMath, BigInteger, and RandomGenerator.
4. 04exceptionsThrowable, Error, Exception. checked vs unchecked.
5. 05try, catch, finallyhow an exception unwinds the stack, frame by frame.
6. 06try-with-resourcesautomatic closing, in reverse order, with suppressed exceptions.
7. 07designing with exceptionscustom exceptions, chaining, and translating across layers.
8. 08optionala box that might be empty. idioms and anti-patterns.
9. 09dates and timeInstant vs LocalDateTime vs ZonedDateTime, and daylight saving traps.
10. 10regular expressionsPattern, Matcher, groups, and how backtracking can melt your cpu.
11. 11loggingSystem.Logger, java.util.logging, SLF4J. levels and where logs go.