Graph Traversal from given start node to end node

package algo;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.Stack;

public class GraphTraversal {
    public static void main(String[] args) {
        Map<String, List<String>> graph = new HashMap<>();
        List<String> aList = new ArrayList<String>();
        aList.add("F");
        aList.add("B");
        aList.add("C");
        graph.put("A", aList);
       
        List<String> bList = new ArrayList<String>();
        bList.add("E");
        bList.add("A");
        bList.add("D");
        graph.put("B", bList);
       
        List<String> dList = new ArrayList<String>();
        dList.add("E");
        dList.add("A");
        dList.add("Z");
        graph.put("D", dList);
       
       
       
        buildPath(graph, "A", "Z");
       
    }
    public static void buildPath(Map<String, List<String>> graph, String start, String end){
        Set<String> processedNode = new HashSet<>();
        Stack<String> stack = new Stack<>();
        processedNode.add(start);
        stack.push(start);
        processPath(graph, processedNode, stack, start, end);
    }
   
    public static void processPath(Map<String, List<String>> graph, Set<String> processedNode, Stack<String> stack, String start, String end){
        if(start.equals(end)){
            System.out.println(stack);
            return;
        }
        List<String> children = graph.get(start);
        if(children != null) {
            for(String child : children){
                if(!processedNode.contains(child)){
                    stack.push(child);
                    processPath(graph, processedNode, stack, child, end);
                }
            }
        }
        stack.pop();
    }
}

ORA-01878: specified field not found in datetime or interval

https://stackoverflow.com/questions/22305466/oracle-date-compare-broken-because-of-dst

How to configure tomcat server with SSL configuration?

1. Create private key and CSR using OpenSSL

openssl genrsa -out www.mydomain.com.key 2048

openssl req -new -sha256 -key www.mydomain.com.key  -out www.mydomain.com.csr

2. Submit CSR file to your Certificate Authority to generate & share valid CA certificates.

Valid CA certificates would have following files

a.  www.mydomain.com.crt

b.  xxxxCARoot.crt

c.  xxxxTrustxxx.crt

d.  xxxxxxxCA2.crt

3. Bundle CA, CA2 and Trust certificate into single file bundle.crt

4. Generate pkcs12 file using below command and provide keystorePass as 'changeit'

>openssl pkcs12 -export -in www.mydomain.com.crt -inkey www.mydomain.com.key -out www.mydomain.com.p12 -name tomcat -CAfile bundle.crt -caname root -chain

5. Configure tomcat server.xml with below <Connector>

<Connector SSLEnabled="true" keystoreFile="conf/ssl/www.mydomain.com.p12" keystorePass="changeit" keystoreType="PKCS12" port="443" protocol="HTTP/1.1" scheme="https" secure="true" sslProtocol="TLSv1.2"/>

How to change tomcat 8 port to 80

To run Tomcat on a port below 1024 in Ubuntu/Unix, the service needs root privileges.
And that you do not want. Use a port redirection via iptables

iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 80 -j REDIRECT --to-port 8080

MongoDB SSL connection command

$ mongo --host <hostname> --port <port> --username username --password --ssl --sslPEMKeyFile <filename> --sslPEMKeyPassword <value> --sslCAFile <filename>

Manage Tablespaces

Create:
CREATE TABLESPACE DATA05 DATAFILE 'D:\app_db12c\oracle\oradata\orcl\sample01.dbf' SIZE 1M AUTOEXTEND ON NEXT 1M;

Extend:
ALTER TABLESPACE DATA05 ADD
  DATAFILE 'D:\app_db12c\oracle\oradata\orcl\sample02.dbf' SIZE 1M
  AUTOEXTEND ON NEXT 1M;

Delete:
DROP TABLESPACE DATA05 INCLUDING CONTENTS AND DATAFILES;

SQLPLUS command to start oracle pdbs

sqlplus sys/xxxxx as sysdba@pdborcl.xxxx.com

SQL*Plus: Release 12.1.0.2.0 Production on Fri Nov 4 12:07:01 2016

Copyright (c) 1982, 2014, Oracle.  All rights reserved.


Connected to:
Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production
With the Partitioning, OLAP, Advanced Analytics and Real Application Testing options

SQL> SELECT name,open_mode from v$pdbs ORDER BY name;

NAME                           OPEN_MODE
------------------------------ ----------
PDB$SEED                       READ ONLY
PDBORCL                        MOUNTED

SQL> alter pluggable database pdborcl open read write;

Pluggable database altered.

SQL> SELECT name,open_mode from v$pdbs ORDER BY name;

NAME                           OPEN_MODE
------------------------------ ----------
PDB$SEED                       READ ONLY
PDBORCL                        READ WRITE

SQL>