1. Online UML
https://www.draw.io/
2. Maven repository
https://mvnrepository.com/
3. PDF Drive is your search engine for PDF files
https://www.pdfdrive.net/
4. Android测试版计划
https://www.google.com/android/beta?rapt=AEjHL4PFgcSCGjO-kzBqr1T2l4VX-P13RWpv8Nxg-WeXXpKVKgm0txeST-cbkgT2gmDlZisoUl-JEiZ7ppWyidpmyJNf1VO2fw
5. Stackoverflow
http://stackoverflow.com/
6. Java World
http://www.javaworld.com/
7. IBM developerWorks
http://www.ibm.com/developerworks/java/
8. Wikipedia
http://en.wikipedia.org/wiki/
9. LeetCode
http://leetcode.com/
10. Github
https://github.com/
11. Program creek
https://www.programcreek.com/
12. Program online
http://www.tutorialspoint.com/codingground.htm
13. Wow! eBook
http://www.wowebook.com/
14. Intellij IDEA 注册码
http://idea.lanyus.com/
15. JAVA67
http://www.java67.com/
16. pt-query-digest
https://www.percona.com/doc/percona-toolkit/LATEST/pt-query-digest.html
17. spring framework libs
http://repo.springsource.org/libs-release-local/org/springframework/spring/
18. Java bytecode viewer
https://github.com/ingokegel/jclasslib/releases
19. Java decompiler
http://javare.cn/
20. Geeks
https://www.geeksforgeeks.org/
21. Insight full logic
http://insightfullogic.com/
22. Sublime
https://www.sublimetext.com/
23. Selenium-release
http://selenium-release.storage.googleapis.com/index.html
24. The online python compiler
https://repl.it/repls/DarkseagreenColorlessRhombus
25. The online goLang compiler
https://repl.it/repls/IvoryLooseConversions
26. Postman
https://developers.sap.com/germany/tutorials/api-tools-postman-install.html