Learn java
Short lessons written around the screening tests employers use. Read one, then take the test.
Equality and String behaviour in JavaHow == differs from equals(), why String is immutable, and how the string pool changes comparison results.Lesson 1
Inheritance, overriding and exceptions in JavaWhich method runs at runtime, what static really means, and how try, catch and finally execute in order.Lesson 2
Collections: ArrayList, HashSet and HashMap in practiceWhich collection to pick, how HashMap put and get behave, and why removing inside a for-each loop throws an exception.Lesson 3
Streams, lambdas and OptionalRead and write filter, map, collect and groupingBy pipelines, use Optional without get(), and avoid reusing a consumed stream.Lesson 4
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