Updated June 20, 2023
Introduction to Cheat Sheet Java
Java is a high-level, object-oriented computer programming language, and Sun Microsystems developed it in 1995. The Java-based applications are mainly executed to bytecode which can be executed on any Java Virtual Machine irrespective of any computer architecture. James Gosling started the Java language project in 1991, and initially, it was termed ‘Oak’ after an Oak tree that stood outside Gosling’s office.
Important Characteristics of Java Language
- It is an object-oriented programming language.
- It is platform-independent, and thus unlike other programming languages, a compilation of Java is not dependent on any platform-specific system.
- From the learning perspective, it is easier to and implements.
- It is architecture-neutral and thus portable.
- It has three layers of authentication patches from a security perspective.
- From the performance perspective, it always ensures proper timecode compilation and high-performance outputs.
- It is more dynamic than its competitors and thus provides added advantages for the developers.
- It is multi-threaded.
- Provides support for the distributed internet environment.
Commands and Content on Cheat Sheet Java
Java has an extensive library, is interactive, extendable, and contains many in-built methods to compute common operations. Below is the Cheat sheet Java commands mentioned, which perform different kinds of operations:
| COMMAND | DESCRIPTION |
| + | To display the next memory section (hexdump-like format) |
| – | To display the previous memory section (hexdump-like format) |
| coreinfo | To display the platform, version information, and command-line arguments |
| basicinfo | To display the main basic information |
| info class | To display the inheritance chain and data information for a specific class |
| info memory | To display and analyze the memory management (tree format) |
| info lock | To display the list of locked objects and available monitors |
| extra memory | To save a mentioned memory range conversion to a binary file |
| heapdump | To generate a heap dump to a file |
| info sym | To display a list of available modules |
| javaclass | To display a list of Java classes |
| javaobject | To display the specific address, the Java object |
| javamonitor | To display the specific address java-monitor |
| javathread | To display specific Java thread information |
| show heapdump | To display the settings of current heap dump values |
| show logging | To display the values of current logging settings |
| snaptrace | To extract trace buffers to a specified file |
Operators: The different types of operators in Java are Comparison (Relational) Operators, Assignment Operators, Logical Operators, Bitwise Operators, Membership Operators, and Identity Operators. The different types of numerical operators are int (signed and unsigned), long, float, and complex numbers.
Comparison Operators: Find below the cheat sheet for Java basic comparison operators.
| OPERATORS | DESCRIPTION / MEANING |
| > | greater than |
| < | less than |
| >= | greater than or equal |
| <= | less than or equal |
| == | equal to |
| != | not equal |
Printing Syntax: Find below the printing syntax used in Java Cheat Sheet.
| SYNTAX | OUTPUT |
| void System.out.print(String S) | To print S |
| void System.out.println(String S) | To print S followed by a new line |
| void System.out.println() | To print a new line |
Loops: The looping operators in Java are while, for, and nested. The nested loops are while, for, do…while, etc. The different loop control statements are break, continue and pass statements.
Identifiers: It is used to identify any function, class, variable, object or module, etc. In the case of Java, the allowed characters for identifiers are all the alphanumeric characters ([A-Z],[a-z],[0-9]), ‘$ ‘(dollar sign), and ‘_’. Java identifiers are also case-sensitive.
Methods for java.lang.Math class: Cheat sheet Java methods available for java.lang.Math classes are as follows
| METHOD | DESCRIPTION |
| static double abs(double a) | Returns the absolute value of a double value |
| static int abs(int a) | Returns the absolute value of an int value |
| static float abs(float a) | Returns the absolute value of a float value |
| static int max(int a, int b) | Returns the greater of two int value |
| static float max(float a, float b) | Returns the greater of two float value |
| static long max(long a long b) | Returns the greater of two long value |
| static int min(int a, int b) | Returns the smaller of two int value |
| static float min(float a float b) | Returns the smaller of two float value |
| static long min(long a long b) | Returns the smaller of two long value |
| static double random() | Returns a positive double value that is greater than or equal to 0.0 but less than 1.0 |
| static double ulp(double d) | Returns the size of an argument ulp |
| static double ulp(float f) | Returns the size of an argument ulp |
| static double sin(double a) | Returns the hyperbolic sine of a double value |
| static double tan(double a) | Returns the trigonometric tangent of an angle |
Free Tips and Tricks for Using Cheat Sheet Java Commands
The Java Cheat Sheet can be run using a command-line window and running the command as different interrelated methods.
- From a programmatic perspective, Java provides a richer and more extensive library method than its competitors, and thus it has become a much preferable language for programmers.
- In the case of Java, primitive classes are preferred to the wrapper classes, thus removing the wrapper classes’ slowness.
- The Java programs can be interpreted by running the codes in the window and executing the programs simultaneously.
- The map function will be applied to all items in an input list.
- The reduce function is used to apply some computation on a list and returns a value.
- In Java, if the string objects are initiated directly without using the constructor, it would be better from the performance perspective.
- As a dynamic programming language, memory allocation in Java using the ‘new’ keyword is necessary. The ‘new’ keyword will show a null pointer exception in the code.
- The conditional expressions can be used to write conditional statements to execute the required computations.
Conclusion
Java is easy to use, and its syntax is easier to remember and code the programs easily. Java can be used in web development technologies using different frameworks and technologies supporting Java. Based on the type of project need, time of work, and other discussed aspects; java should be used to reach the desired goal.
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