SCJP, SCJD, SCWCD, OCPJBCD
SCJA 1.0, SCJP 1.4, SCWCD 1.4, SCBCD 1.3, SCJP 5.0, SCEA 5, SCBCD 5; OCUP - Fundamental, Intermediate and Advanced; IBM Certified Solution Designer - OOAD, vUML 2; SpringSource Certified Spring Professional
Exam 1Z0-810: Upgrade to Java SE 8 Programmer Study Guide and Quiz
Exam 1Z0-817: Upgrade OCP Java 6, 7 and 8 to Java SE 11 Developer Study Guide and Quiz
Most of the programming problems can't be solved because you don't know what the exact problem is.
Defining your problem correctly leads you to the right solution.
Dilshan Edirisuriya SCJP1.4, SCWCD1.4, SCBCD 5