AlgoExpert.io
LeetCode
Interview Cake
Daily Coding Problem
interviewing.io
CodingInterview
HackerRank
Codechef
Java Decompiler
Decompiler.com
CFR
Bytecode Viewer
Java Class File Editor
Cavaj Java Decompiler
ShenmeApp Java Decompiler
.NET Reflector
AlgoExpert.ioTheir interview questions are pretty basic and the whole product is pretty much useless. Waste of time and money.
LeetCode - Practice and level up your development skills and prepare for technical interviews.
Decompiler.com - Online Java and Android decompiler. Just drag and drop .JAR or .APK file and browse decompiled content online.
Interview Cake - Free practice programming interview questions. Interview Cake helps you prep for interviews to land offers at companies like Google and Facebook.
CFR - CFR is a JVM bytecode decompiler - it will decompile modern Java features - up to and including much of Java 9, but is written entirely in Java 6, so will work anywhere! - It'll even make a decent go of turning class files from other JVM languages (โฆ
Daily Coding Problem - Get exceptionally good at coding interviews
Bytecode Viewer - A Java 8 Jar & Android APK Reverse Engineering Suite (Decompiler, Editor, Debugger & More)