免費Simple Java (非常簡單的英文)

        Simple Java 是常見的Java問題的集合。它已被轉換為PDF格式，你可以在這里下載。 

        Foreword

        1. Strings and Arrays

• What is string immutability?
• How does substring () work?
• Why string is immutable?
• Create Java string Using ” ” or constructor?
• Is string passed by reference?
• length vs. length ()
• How to check if an array contains a value efficiently?
• What is varargs?
• What exactly is null?

        2. Common Methods

• Comparator vs. Comparable
• The contract between hashCode () and equals ()
• Java passes object by reference or by value?
• Iteration vs. recursion

        3. Classes and Interfaces

• Overloading vs. overriding
• What is instance initializer?
• Fields can not be overridden?
• Inheritance vs. composition
• How to use Java Enum?
• How many types of inner classes?
• What is inner interface?
• Constructors of sub and super classes?
• 4 access levels
• When to use private constructors?

        4. Collections & Generics

• Class hierarchy of Collection and Map
• A TreeSet example
• Deep understanding of Arrays.sort (T[], Comparator < ? super T > c)
• How do developers sort?
• ArrayList vs. LinkedList vs. Vector
• java.util.ConcurrentModificationException
• HashSet vs. TreeSet vs. LinkedHashSet
• HashMap vs. TreeMap vs. HashTable vs. LinkedHashMap
• Efficient counter
• Frequently used methods of HashMap
• What is type erasure?
• Why do we need generic types?
• Set vs. Set
• What's the best way of converting Array to ArrayList?

        5. Exceptions

• How exception handling works?
• Class hierarchy of exceptions

        6. Concurrency

• Monitors – the key idea of Java synchronization
• How to make a method thread-safe?
• join ()
• notify () and wait ()
• Create thread by overriding

        7. I/O & Database

• Read file line by line
• Write file line by line
• FileOutputStream vs. FileWriter
• Should .close () be put in finally block or not?
• Java serialization
• How to use properties file?

        8. Compiler and JVM

• JVM run-time data areas
• How does Java handle aliasing？
• What does an array look like in memory?
• What is memory leak?
• What can be learned from "Hello World"?
• Whan and how a class is loaded and initialized?
• Static type checking
• Generate code for overloaded and overridden methods?

        9. Top collections

• Top 10 mistakes Java developers make
• Top 10 methods for Java arrays
• Top 10 questions of Java strings
• Top 10 questions for Java regular expression
• Top 10 questions about Java exceptions
• Top 10 questions about Java collections
• Top 9 questions about Java maps
• The most widely used Java libraries
• Top 10 websites for advanced level Java developers
• Top 10 books for advanced level Java developers
• Top 100 High-quality Java blogs
• Top 10 algorithms for coding interview
• Top 8 diagrams for understanding Java

        10. Popular Libraries, Frameworks and Tools

• Reflection tutorial
• What is framework?
• Why do we need Java web frameworks like Struts 2?
• What is Servlet Container? What is Tomcat?
• What is aspect-oriented Programming?
• Library vs. framework?
• Spring
• Open source projects using Spring framework
• Design patterns in stories
• Struts 2
• How CVS works?
• Why do we need software testing?
• Convert java jar file to exe
• Guava
• Log4j
• JSoup
• Swing

        11. Others

• How to build your own library?
• How to get double?
• Java and computer science courses
• Java vs. Python: Basic Syntax, Date Types
• How to write a crawler?
• 8 things programmers can do at weekends
• Declaration, initialization and scoping
• Date formatting (add more)
• Path of package and class