Object References

Remarks

This should help you understand a “Null Pointer Exception” – one gets one of those because an object reference is null, but the program code expects the program to use something in that object reference. However, that deserves its own topic…

Found a mistake? Have a question or improvement idea? Let me know.

Object References:

*Object References

*Object References as method parameters

Table Of Contents

1Getting started with Java

5Lambda Expressions

12InputStreams and OutputStreams

13Default Methods

14Classes and Objects

15Basic Control structures

16Concurrent Programming Threads

19Visibility controlling access to members of a class

20Regular Expressions

22Documenting Java Code

23Executor, ExecutorService and Thread pools

24Object Class Methods and Constructor

26Primitive Data Types

30HttpURLConnection

34Calendar and its Subclasses

35Nashorn JavaScript engine

36Java Native Interface (JNI)

37Remote Method Invocation (RMI)

38Iterator and Iterable

42Properties Class

44Reflection API

47Serialization

49Random Number Generation

52StringBuilder

53Refernce Data Types

54Bit Manipulation

56Encapsulation

57Type Conversion

60RSA Encryption

61Varargs Variable Arguments

64static keyword

65Disassembling and Decompling

66Resources on classpath

67log4j, log4j2

69Oracle Official Code Standard

70Character encoding

71Java Memory Management

72Immutable Objects

73Object Cloning

74Alternative Collections

76BufferedWriter

79Comparable and Comparator

80JVM Tool Interface

81Nested and Inner Classes

82Apache Commons Lang

83Getters and Setter

84The Classpath

85Bytecode Modification

86XML Parsing using JAXP

87Reference Types

88Localization and Internationalization

90XML XPath Evaluation

91Performance Tuning

92Parallel programming with ForkJoin framework

93Common Pitfalls

94Non-Access Modifiers

95Java Compiler

97Installing Java Standard Edition

99Command line argument processing

100Dates and Time using java.time

101Fluent Interface

102XOM - XML Object Model

103Just in Time JIT compiler

104FTP File Transfer Protocol

105Java Native Access JNI

107Pitfalls - exceptions

108Pitfalls - language syntax

109ServiceLoader

110ClasssLoader

111Object References

112Pitfalss - performance

113Creating Images Programmatically

115NIO Networking

116New File I/O

117Secure objects

118Pitfalls - threads and concurrency

119Splitting a string into fixed length parts

120Pitfalls - nulls and NullPointerException

121SecurityManager

123super keyword

124java.util.Objects class

125Java command: java and javaw

126Atomic types

127Floating Point Operations

128Converting to and from strings

129sun.misc.Unsafe

130Java Memory Model

131Java deployment

132Java plugin system implementations

133Queues and deques

134Runtime commands

135NumberFormat

136Security and Cryptograhy

137Java Virtual Machine JVM

138Unit Testing

142Java SE 8 Features

143Java SE 7 Features

145Concurrency and Money

146Concurrent Collections

147Using ThreadPoolExecutor in multi-threaded applications

148Java Editions, versions, releases and distributions

149Dynamic method dispatch

150JMX

151Security and cryptography

152Generating Java Code

155Collection Factory Methods

156Multi-release JAR files

157Stack-Walking API

158TreeMap and TreeSet

160Java Sockets

161Using other scripting languages in Java

162Functional interfaces

163List vs. set

166Deque interface

168EnumSet class

169Local Inner class

170Java Print Service

171Immutable class

172String Tokenizer

173File upload to S3 / AWS

174Readers and writers

176Enum starting with a number

179LinkedHashMap

180StringBuffer

181Choosing Collections

182C++ Comparison

183CompletableFuture

184Contributors