Java 8

McGraw-Hill Osborne Media

Java 8 Preview Sampler (English Edition)        

O'Reilly Media

Java 8 Lambdas: Pragmatic Functional Programming

Java 8 for Beginners: The Advanced Java (English Edition)

Top 50 Java 8 Stream Interview Questions & Answers (English Edition)

Sybex

OCA / OCP Java SE 8 Programmer Certification Kit: Exam 1Z0-808 and Exam 1Z0-809

Independently published

Java 8 Interview Q&A: Master Java 8 Interview Questions And Prepar For Technical Interviews

Addison Wesley

Effective Java                                  

Wiley

OCA: Oracle Certified Associate Java SE 8 Programmer I Study Guide: Exam 1Z0-808 (Sybex Study Guide)

McGraw-Hill Education

OCA Java SE 8 Programmer I Exam Guide (Exams 1Z0-808) (CERTIFICATION & CAREER - OMG)

For Dummies

Java For Dummies, 8th Edition (For Dummies (Computer/Tech))