Java programming knowledge

Java2 test question list:
1. What is abstraction?
2. What are the three principles of object-oriented programming?
3. How to define an identifier?
4. What are Java keywords? Is null a Java keyword?
5. What data types does Java have? What are their descriptions? How many bits are byte, short, Int, long, Char, float, double, and Boolean?
6. List common escape characters?
7. How to define the Java array type?
8. List common arithmetic operators? What is the difference between ++ A and A ++?
9. List common bitwise operators?
10. List common Relational operators?
11. List common Boolean logical operators?
12. Can I write an example of a ternary operator?
13. List the priority of operators?
14. Try to list the keywords of program control statements in Java? An example is provided?
15. How to define a class?
16. Does one class inherit another class? How do I call Constructors?
17. How can I access static methods of a class?
18. How to inherit a class?
19. How to define an interface?
20. What is the difference between an interface and an abstract class definition?
21. Can you describe how Java collects garbage?
22. How to call the finalize () method?
23. What is method overload?
24. Complete a class to pass an object as a function parameter?
25. How to define a Java internal class? Describe the usage of Java internal classes in detail, and give an example?
26. Differences between public, protected, private, and default classes
27. How to prevent a method from being overloaded?
28. What is the meaning of package in Java?
29. list several common exceptions in Java?
30. How to throw an exception? Try to write out a try and catch example.
31. How can I use Finally, throw, and throws?
32. How to Create a Java multi-threaded program? Try to write an example?
33. What is the concept of thread synchronization?
34. List common Java. Io byte stream classes? Try to create a new file, write characters to the file, and then try to read it out?
35. How to understand instance?
36. How to understand the Java keyword strictfp?
37. How to use the local method in Java?
38. How to Use the string method for string processing?
39. List common methods in the string class, such as how to create a string, how to connect to a string, how to obtain a string, how to intercept a string from a string, and how to compare strings.
40. What is the difference between equals () and =?
41. How to obtain the index of a character in a string?
42. How does a string replace certain characters and trim spaces?
43. How to Use the valueof method to convert other types of data to strings?
44. What is the difference between the stringbuffer method and the string method? List common methods in stringbuffer?
45. How to split strings, such as using and splitting strings?
46. List classes in Java. Lang?
47. List the interfaces in Java. Lang?
48. How to obtain information about memory management in Java?
49. How to call methods in system?
50. How to Use the clone () and cloneable methods?
51. Describe the class?
52. List common math methods?
53. How to Use the reflection mechanism in Java?
54. What is the definition and scope of use of the collection, list, set, and sortedset interfaces?
55. How to Use the arraylist class?
56. How to Use the sort list class? What is the difference between the above and above?
57. How to Use the hashset class?
58. How to Use the treeset class?
59. How to aggregate class sets through iterative functions? An example is provided?
60. How to Handle ing in Java?
61. How to Use the hashmap class?
62. How to Use the treemap class?
63. How to Use the sort method of arrays array?
64. How to Use the Vector class?
65. How to Use the enumeration interface?
66. How to Use the Stack class?
67. How to Use the hashtable class?
68. How to use the dictionary class?
69. How to Use the properties class?
70. How to Use the stringtokenizer class?
71. How to Use bitset classes?
72. How to Use the java. util. Date class?
73. How to Use the java. SQL. Date class?
74. How to Use the calendar class?
75. How to Use the gregoriancalendar class?
76. How to Use the timezone class?
77. How to Use the simpletimezone class?
78. How to use the local class?
79. How to Use the random class?
80. How to Use the observable class?
81. How to Use timer and timertask classes?
82. What about the java.util.zip package?
83. About the java. util. jar package?
84. How to Use the serializable interface?
85. What is the structure of the java.net package?
86. How to Use the inetaddress class? And inet4address and inet6address?
87. What about TCP/IP sockets? How to Create a socket object?
88. About URL classes?
89. How to Use the urlconnection class?
90. About TCP/IP server sockets?
91. How to Use the datagrampacket class?
92. How can I use the Applet Class?
93. How to Use the getdocumentbase method?
94. How to Use the getappletcontext method?
95. About Java small Application Event Processing?
96. For the main event classes in Java. AWT. event, list common classes?
97. Understanding about event sources?
98. What about the event listener interface?
99. How to Use the actionlistener interface?
100. How can I use the adjustmentlistener interface?
101. How to Use the componentlistener interface?
102. How to Use the focuslistener interface?
103. How to Use the itemlistener interface?
104. Use of the windowlistener Interface
105. Describe the adapter class?
106. Describe the inner class?
107. What about anonymous internal classes?
108. How to Use the AWT layout manager?
109. Brief introduction to the java. AWT. Image package?
110. How to implement animation?
111. List the core Java packages?
112. How to Use the RMI Technology in Java?
113. What about the java. Text package? How to Use the dateformat class?
114. What is the definition of JavaBeans?
115. How to Create a jar file?
116. Brief introduction and use of swing packages?
117. How to understand and use Java. Beans?
118. How to understand and use Java. Security?
119. How to understand and use the decimalformat class?
120. How to understand and use the javax. Naming. LDAP package?
121. How to understand and use the javax. RMI. CORBA package?
122. How to understand and use the javax. SQL package?
123. How to understand and use the javax. xml package?
124. How to understand and use the enum <E extends Enum <E> class?
125. How to understand and use bigdecimal classes?
126. How can I understand and use remote interfaces?
127. How do I understand and use the timestamp interface?
128. What is the understanding and use of the drivermanager class?
129. How can I understand and use logger classes?
130. What are the understandings and descriptions of design patterns?
131. What about Java JDBC?