Skip to content

CMD

Jump to bottom
Yash edited this page Aug 6, 2019 · 2 revisions

Windows Command Line [ping, taskkill, netstat, telnet], Keytool [ssl, codesigner]

NETSTAT.exe wiki

netstat (network statistics): In computing, netstat is a command-line network utility that displays network connections for Transmission Control Protocol, routing tables, and a number of network interface and network protocol statistics.

Display current TCP/IP network connections and protocol statistics.

TASKKILL

TaskKillmicrosoft.com : Kill process from command line (CMD)

Example form processKill.bat, NetStart_TaskKill.java

D:\Yash>netstat -ano | findstr 12516
  TCP    0.0.0.0:80             0.0.0.0:0              LISTENING       12516
  TCP    0.0.0.0:443            0.0.0.0:0              LISTENING       12516
  TCP    [::]:80                [::]:0                 LISTENING       12516
  TCP    [::]:443               [::]:0                 LISTENING       12516
  
D:\Yash>taskkill /f /pid 6392
 SUCCESS: The process with PID 6392 has been terminated.

Find the pid of the process running in the port number (e.g., 8080)

netstat -ano | findStr "8080"

tasklist /fi "pid eq 2216"

WMIC.exe - Get CPU Information With Wmic

WMIC CPU Get /Format:List CPU_Cores_JVM.java

How to Free TCP/UDP Port on Windows Using netstat and taskkill?

boot-two-way-ssl-example

How to check an SMTP connection with a manual telnet session

SMTP email in PuTTY - https://superuser.com/a/245145/559653

ARP - ARP stands for Address Resolution Protocol.

NetStart_TaskKill

In a class-based object-oriented language, in general, state is carried by instances, methods are carried by classes, and inheritance is only of structure and behavior. Basic, Refactoring Techniques

Method signature: It consists of method name and parameter list (number/type/order of the parameters). methodName(parametersList y). An instance method in a subclass with the same signature and return type as an instance method in the super-class overrides the super-class's method.

Java OOP concepts
Class  - Collection of a common features of a group of object [static/instance Fields, blocks and Methods]
Object - Instance of a class (instance fields)
Abstraction - Process of hiding complex info and providing required info like API, Marker Interfaces ...
Encapsulation(Security) - Class Binding up with data members(fields) and member functions.
Inheritance  (Reusability by placing common code in single class)
 1. Multilevel - {A -> B -> C} 2. Multiple - Diamond problem {A <- (B) -> C} [Java not supports] 3. Cyclic {A <-> B} [Java not supports]
 * Is-A   Relation - Class A extends B
 * Hash-A Relation - Class A { B obj = new B(); } - (Composition/Aggregation)
Polymorphism (Flexibility) 1. Compile-Time Overloading    2. Runtime Overriding  [Greek - "many forms"]


int[] arr = {1,2,3}; int arrLength = arr.length;   // Fixed length of sequential blocks to hold same data type
String str = "Yash"; int strLength = str.length(); // Immutable Object value can't be changed.

List<?> collections = new ArrayList<String>(); int collectionGroupSize = collections.size();
Map<?, ?> mapEntry = new HashMap<String, String>();
Set<?> keySet = mapEntry.keySet(); // Set of Key's
Set<?> entrySet = mapEntry.entrySet(); // Set of Entries [Key, Value]

// Immutable Objects once created they can't be modified. final class Integer/String/Employee
Integer val = Integer.valueOf("100"); String str2 = String.valueOf(100); // Immutable classes
final class Employee { // All Wrapper classes, java.util.UUID, java.io.File ...
    private final String empName; // Field as Final(values can be assigned only once) Only getter functions.
    public Employee(String name) { this.empName = name; }
}

Native Java Code for Hashtable.h, Hashtable.cpp SQL API.

You can check your current JDK and JRE versions on your command prompt respectively,

  • JDK javac -version [C:\Program Files\Java\jdk1.8.0_121\bin] o/p: javac 1.8.0_121
  • JRE java -version [C:\Program Files\Java\jdk1.8.0_121\bin] o/P: java version "1.8.0_102"

JAVA_HOME - Must be set to JDK otherwise maven projects leads to compilation error. [ERROR] No compiler is provided in this environment. Perhaps you are running on a JRE rather than a JDK? C:\Softwares\OpenJDK\, 7-zip

Fatal error compiling: invalid target release: JRE and JDK must be of same version 1.8.0.XXX

Disable TLS 1.0 and 1.1security-libs/javax.net.ssl: TLS 1.0 and 1.1 are versions of the TLS protocol that are no longer considered secure and have been superseded by more secure and modern versions (TLS 1.2 and 1.3).

Core Java

Stack Posts

Clone this wiki locally