Develop Reference

Processbuilder output as it is executing

I would like the output of a shell command to go to a textArea in my java program as the shell command executes rather than after it has completed.
Current code that waits until process is complete and then shows the output:
ProcessBuilder builder = new ProcessBuilder("shell_command.sh");
builder.redirectErrorStream(true);
try {
Process p = builder.start();
String s;
BufferedReader stdout = new BufferedReader (
new InputStreamReader(p.getInputStream()));
while ((s = stdout.readLine()) != null) {
logPanel.addText(s + "\r\n"); // adds text to a textArea
}
System.out.println("Exit value: " + p.waitFor());
p.getInputStream().close();
p.getOutputStream().close();
p.getErrorStream().close();
} catch (Exception ex) {
ex.printStackTrace();
}

In UI thread...
(new Thread(new ShellCommand(logPanel) ) ).start();
New Class...
class ShellCommand implements Runnable {
LogPanel logPanel; // textArea
ShellCommand(LogPanel logPanel) {
this.logPanel = logPanel;
}
public void run() {
try {
ProcessBuilder builder = new ProcessBuilder("shell_command.sh");
builder.redirectErrorStream(true);
Process p = builder.start();
String s;
BufferedReader stdout = new BufferedReader(new
InputStreamReader(p.getInputStream()));
while ((s = stdout.readLine()) != null) {
logPanel.addText(s + "\r\n");
}
System.out.println("Exit value: " + p.waitFor());
p.getInputStream().close();
p.getOutputStream().close();
p.getErrorStream().close();
JOptionPane.showMessageDialog(null, "Done", "Message",
JOptionPane.INFORMATION_MESSAGE);
} catch (Exception ex) {
ex.printStackTrace();
}
}
}
}

how to create a powershell remote session from inside a Java program?

I have the following code to connect to a remote machine and execute commands.It is working if I create a new session for each Invoke-Command call to the remote machine. I don't want to create a new session each time I use Invoke-Command as that will not scale for thousands of commands on hundreds of machines concurrently and session creation itself is a big overhead. I need a way so that I can reuse the same session object in the $session powershell variable for multiple Invoke-Command calls to the remote machines.
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Scanner;
public class PowerShellSession {
private static String subModule = "PowerShellSession";
String targetIpAddress;
String username;
String password;
public static Object connectPShellLock = new Object();
public PowerShellSession() {}
public void exec(String cmd, String credentials) {
String ex = "Invoke-Command -Session $session -ScriptBlock {" + cmd + "} -Computer " + targetIpAddress;
String[] args = new String[] { "powershell", ex};
try {
execRemote(args);
} catch (IOException e) {
e.printStackTrace();
}
}
public void close() {
String command = "Exit-PSSession";
String[] args = new String[] { "powershell", command};
try {
execRemote(args);
} catch (IOException e) {
e.printStackTrace();
}
}
private String getCredentials(String domain, String userName,
String password) throws IOException {
String creds = "$PlainPassword ='" + password
+ "'; $SecurePassword = $PlainPassword | ConvertTo-SecureString -AsPlainText -Force;"
+ "$mycred = new-object -typename System.Management.Automation.PSCredential('" + userName + "', $SecurePassword);";
creds += "$session = New-PSSession -ComputerName " + domain + " -Credential $mycred;";
String[] args = new String[] { "powershell", creds};
execRemote(args);
return creds;
}
private void execRemote(String[] arguments) throws IOException {
ProcessBuilder builder = new ProcessBuilder(arguments);
builder.redirectErrorStream(true);
Process process = builder.start();
doProcessIO(process);
}
// Do the IO for a passed process
private void doProcessIO(Process p) throws IOException {
p.getOutputStream().close();
String line;
System.out.println("Output:");
BufferedReader stdout = new BufferedReader(new InputStreamReader(
p.getInputStream()));
while ((line = stdout.readLine()) != null) {
System.out.println(line);
}
stdout.close();
System.out.println("Error:");
BufferedReader stderr = new BufferedReader(new InputStreamReader(
p.getErrorStream()));
while ((line = stderr.readLine()) != null) {
System.out.println(line);
}
stderr.close();
// System.out.println("Done");
}
public static void main(String[] args) throws IOException {
PowerShellSession psSession = new PowerShellSession();
String credentials = psSession.getCredentials("9.120.241.195", "username", "password");
psSession.targetIpAddress = "9.120.241.195";
if(!credentials.equals("")) {
Scanner input = new Scanner(System.in);
while(true) {
System.out.print("PS C:\\Windows\\system32> ");
String cmd = input.nextLine();
if(cmd.equals("q") || cmd.equals("e") || cmd.equals("quit") || cmd.equals("exit")) break;
psSession.username = "username";
psSession.password = "password";
psSession.exec(cmd, "");
}
System.out.println("Finished PowerShell remote session.");
input.close();
}
psSession.close();
}
}

See there are lot of logics involves in this which can help you.
Your session invoking is fine; But you cannot directly run a PS command like that. You have to invoke the powershell.exe first then you have to give the respective remote commands what you want to execute.
Finally you have execute the command you will prepare. Let me share you a sample code:
public String executeScript(String psFileName, Systems system) throws NMAException {
Runtime runtime = Runtime.getRuntime();
String filePath = ApplicationProperties.getPropertyValue("powershell.scripts.location");
String command;
switch (psFileName) {
case "TerminalServersSystemInfo.ps1":
command = POWERSHELL + filePath + psFileName + " " + system.getPassword() + " " + system.getUserName()
+ " " + system.getSystemName();
break;
case "SQLServerInfo.ps1":
command = POWERSHELL + filePath + psFileName + " " + system.getSystemName() + " "
+ system.getUserName() + " " + system.getPassword();
break;
case "MyPS.ps1":
{
command = POWERSHELL + filePath + psFileName + " " + system.getSystemName() + " "
+ system.getUserName()
+ " " + system.getPassword() + " " + system.getDatabaseName();
break;
}
default:
throw new NMAException("not available");
}
Here is how you should form the command object in Java and then you should execute this:
powershell -ExecutionPolicy Bypass -NoLogo -NoProfile -Command {Invoke-command ......}
For triggering a PS file you can use the -Filepath switch.
Next this will help you in executing that:
proc = runtime.exec(command);
proc.getOutputStream().close();
InputStream is = proc.getInputStream();
InputStreamReader isr = new InputStreamReader(is);
BufferedReader reader = new BufferedReader(isr);
StringBuilder sb = new StringBuilder();
String line;
while ((line = reader.readLine()) != null) {
sb.append(line);
}
reader.close();
proc.getOutputStream().close();
LOGGER.info("Command: " + command);
LOGGER.info("Result:" + sb.toString());
return sb.toString();
Hope it gives you a set off.

public class PowerShellSession {
private static String subModule = "PowerShellSession";
String targetIpAddress;
String username;
String password;
public static Object connectPShellLock = new Object();
public PowerShellSession() {}
public void exec(String cmd, String credentials) {
String ex = credentials +" Invoke-Command -ScriptBlock {" + cmd + "} -ComputerName " + targetIpAddress +" -Credential $mycred";
String[] args = new String[] { "powershell", ex};
try {
execRemote(args);
} catch (IOException e) {
e.printStackTrace();
}
}
public void close() {
String command = "Exit-PSSession";
String[] args = new String[] { "powershell", command};
try {
execRemote(args);
} catch (IOException e) {
e.printStackTrace();
}
}
private String getCredentials(String domain, String userName,
String password) throws IOException {
String creds = "$Username = '"+userName+"';$PlainPassword ='" + password
+ "'; $SecurePassword = ConvertTo-SecureString -AsPlainText $PlainPassword -Force;"
+ "$mycred = New-Object System.Management.Automation.PSCredential -ArgumentList $Username, $SecurePassword;";
//creds += "$session = New-PSSession -ComputerName " + domain + " -Credential $mycred;";
String[] args = new String[] { "powershell", creds};
execRemote(args);
return creds;
}
private void execRemote(String[] arguments) throws IOException {
ProcessBuilder builder = new ProcessBuilder(arguments);
builder.redirectErrorStream(true);
Process process = builder.start();
doProcessIO(process);
}
// Do the IO for a passed process
private void doProcessIO(Process p) throws IOException {
p.getOutputStream().close();
String line;
System.out.println("Output:");
BufferedReader stdout = new BufferedReader(new InputStreamReader(
p.getInputStream()));
while ((line = stdout.readLine()) != null) {
System.out.println(line);
}
stdout.close();
System.out.println("Error:");
BufferedReader stderr = new BufferedReader(new InputStreamReader(
p.getErrorStream()));
while ((line = stderr.readLine()) != null) {
System.out.println(line);
}
stderr.close();
System.out.println("Done");
}
public static void main(String[] args) throws IOException {
PropertiesFileReader propReader = new PropertiesFileReader(System.getProperty("user.dir")+"/cred.properties");
String user = propReader.getPropertyData("user");
String pass = propReader.getPropertyData("pass");
String ip_add = propReader.getPropertyData("ip");
PowerShellSession psSession = new PowerShellSession();
String credentials = psSession.getCredentials(ip_add, user, pass);
psSession.targetIpAddress = ip_add;//;
String cmdd = propReader.getPropertyData("command");//"Get-Culture";
if(!credentials.equals("")) {
psSession.exec(cmdd, credentials);
System.out.println("Finished PowerShell remote session.");
}
psSession.close();
}
}

Java: Client-Server, chat broadcasting

I"m working on a Client-Server chat program for a university project and I have little programming background. I've made 3 classes: ChatClient, ChatServer and ChatServerThread. I can currently have multiple clients connected and talking to the server at any time.
Although one of the requirements that I'm having the most difficulty is this: "Any message typed from 1 client is sent to all other clients" and also "Both sent and received messages should be displayed".
I've spent the last few nights just trying to get this extra bit of functionality working but have had no luck.
I've been reading and looking around for a while but I have lots of difficulty adapting online examples to my work. I've read that I should be creating a list of sockets and then iterate through the list and send data to everyone in the list, which makes sense in my head but gives me a headache when I try implementing it. Any help with this would be very greatly appreciated. Extra points if anyone can give me some insight on how I could encrypt the sent data.
ChatClient
import java.net.*;
import java.io.*;
public class ChatClient {
private Socket socket = null;
private DataInputStream console = null;
private DataOutputStream streamOut = null;
private String myName = null;
private BufferedReader StreamIn = null;
private String response = null;
public ChatClient(String serverName, int serverPort) {
try {
console = new DataInputStream(System.in);
System.out.println("What is your name?");
myName = console.readLine();
System.out.println(myName + " <" + InetAddress.getLocalHost() + "> ");
} catch (IOException ioe) {
System.out.println("Unexpected exception: " + ioe.getMessage());
}
System.out.println("Establishing connection. Please wait ...");
try {
socket = new Socket(serverName, serverPort);
System.out.println("Connected: " + socket);
StreamIn = new BufferedReader(new InputStreamReader(socket.getInputStream()));
streamOut = new DataOutputStream(socket.getOutputStream());
streamOut.writeUTF(":" + myName + " <" + InetAddress.getLocalHost() + "> HAS JOINED");
streamOut.flush();
} catch (UnknownHostException uhe) {
System.out.println("Host unknown: " + uhe.getMessage());
} catch (IOException ioe) {
System.out.println("Unexpected exception: " + ioe.getMessage());
}
String line = "";
while (!line.equals(".bye")) {
try {
line = console.readLine();
streamOut.writeUTF(myName + " <" + InetAddress.getLocalHost() + "> : " + line);
streamOut.flush();
} catch (IOException ioe) {
System.out.println("Sending error: " + ioe.getMessage());
}
}
}
public void stop() {
try {
if (console != null) console.close();
if (streamOut != null) streamOut.close();
if (socket != null) socket.close();
} catch (IOException ioe) {
System.out.println("Error closing ...");
}
}
public static void main(String args[]) {
ChatClient client = null;
if (args.length != 2)
System.out.println("Usage: java ChatClient host port");
else
client = new ChatClient(args[0], Integer.parseInt(args[1]));
}
}
ChatServer
import java.net.*;
import java.io.*;
import java.util.*;
public class ChatServer implements Runnable {
private ServerSocket server = null;
private Thread thread = null;
private ChatServerThread client = null;
private String clientSentence = null;
private int peers = 0;
private List clients = new ArrayList();
final List sockets = new ArrayList();
public ChatServer(int port) {
try {
System.out.println("Binding to port " + port + ", please wait ...");
server = new ServerSocket(port);
System.out.println("Server started: " + server);
start();
} catch (IOException ioe) {
System.out.println(ioe);
}
}
public void run() {
while (thread != null) {
try {
System.out.println("Waiting for a client ...");
addThread(server.accept());
} catch (IOException ie) {
System.out.println("Acceptance Error: " + ie);
}
}
}
public void addThread(Socket socket) {
System.out.println("Client accepted: " + socket);
client = new ChatServerThread(this, socket);
try {
client.open();
client.start();
} catch (IOException ioe) {
System.out.println("Error opening thread: " + ioe);
}
}
public void start() {
if (thread == null) {
thread = new Thread(this);
thread.start();
}
}
public void stop() {
if (thread != null) {
thread.stop();
thread = null;
}
}
public void increment(String sentence) {
peers++;
String[] info = sentence.split(" ");
String name = info[0].replace(":", "");
System.out.println(name + " Has joined the room, we now have " + peers + " peer(s).");
clients.add(name);
}
public Boolean isAllowed(String name, Socket socket) {
try {
String stringSearch = name;
BufferedReader bf = new BufferedReader(new FileReader("allowed.txt"));
int linecount = 0;
String line = "";
System.out.println("Searching for " + stringSearch + " in file...");
while ((line = bf.readLine()) != null) {
linecount++;
String[] words = line.split(" ");
for (String word : words) {
if (word.equals(stringSearch)) {
System.out.println("User is allowed");
registerSocket(socket);
return true;
}
}
}
bf.close();
} catch (IOException e) {
System.out.println("IO Error Occurred: " + e.toString());
}
System.out.println("User is not allowed");
return false;
}
public void showAll() {
for (int i = 0; i < clients.size(); i++) {
System.out.print(clients.get(i));
}
}
public void registerSocket(Socket socket) {
//socket = new DataOutputStream(socket.getOutputStream());
sockets.add(socket);
for (int i = 0; i < sockets.size(); i++) {
System.out.println(sockets.get(i));
}
}
public static void main(String args[]) {
ChatServer server = null;
if (args.length != 1)
System.out.println("Usage: java ChatServer port");
else
server = new ChatServer(Integer.parseInt(args[0]));
}
}
ChatServerThread
import java.net.*;
import java.io.*;
public class ChatServerThread extends Thread {
private Socket socket = null;
private ChatServer server = null;
private int ID = -1;
private DataInputStream streamIn = null;
private String clientSentence = null;
public String newGuy = null;
DataOutputStream streamOut = null;
public ChatServerThread(ChatServer _server, Socket _socket) {
server = _server;
socket = _socket;
ID = socket.getPort();
}
public void run() {
System.out.println("Server Thread " + ID + " running.");
while (true) {
try {
String sentence = streamIn.readUTF();
//System.out.println(sentence);
char c = sentence.charAt(0);
String[] command = null;
command = sentence.split(" ");
String name = command[0].substring(1);
System.out.println("Sending out: " + sentence + " via ");
streamOut.writeBytes(sentence);
if (c == ':') {
if (server.isAllowed(name, socket))
server.increment(sentence);
else {
close();
}
}
} catch (IOException ioe) {
}
}
}
public void open() throws IOException {
streamIn = new DataInputStream(new BufferedInputStream(socket.getInputStream()));
}
public void close() throws IOException {
if (socket != null) socket.close();
if (streamIn != null) streamIn.close();
}
}

JAVA pdf response error in implementing http 1 socket programming

I run my java webserver on port 6799
My directory has a txt.txt file and pdf.pdf file
When I give localhost:6799/txt.txt, it gives perfect output saying
GET /txt.txt HTTP/1.1HTTP/1.0 200 OK
Content-type: text/plain
This is a very simple text file
But when I give localhost:6799/pdf.pdf from browser, it gives java.lang.NullPointerException
This is my code
import java.net.*;
public final class WebServer {
public static void main(String args[]) throws Exception {
int port = 6799;
System.out.println("\nListening on port " + port);
ServerSocket listen = new ServerSocket(port);
while (true) {
Socket socket = listen.accept();
HttpRequest request = new HttpRequest(socket);
Thread thread = new Thread(request);
thread.start();
}
}
}
--
import java.io.*;
import java.net.*;
import java.util.StringTokenizer;
public final class HttpRequest implements Runnable {
final String CRLF = "\r\n";
Socket socket;
public HttpRequest(Socket socket) throws Exception {
this.socket = socket;
}
#Override
public void run() {
try {
processRequest();
} catch (Exception e) {
System.out.println(e);
}
}
private void processRequest() throws Exception {
BufferedReader br;
DataOutputStream dos;
try (InputStream is = socket.getInputStream()) {
br = new BufferedReader(new InputStreamReader(is));
String requestline = br.readLine();
System.out.println("\n" + requestline);
String headerLine = null;
while ((headerLine = br.readLine()).length() != 0) {
System.out.println(headerLine);
}
dos = new DataOutputStream(socket.getOutputStream());
dos.writeBytes(requestline);
StringTokenizer tokens = new StringTokenizer(requestline);
tokens.nextToken(); // skip over the method, which should be "GET"
String fileName = tokens.nextToken();
// Prepend a "." so that file request is within the current directory.
fileName = "." + fileName;
FileInputStream fis = null;
boolean fileExists = true;
try {
fis = new FileInputStream(fileName);
} catch (FileNotFoundException e) {
fileExists = false;
}
String statusLine = null;
String contentTypeLine = null;
String entityBody = null;
if (fileExists) {
statusLine = "HTTP/1.0 200 OK" + CRLF;
contentTypeLine = "Content-type: " + contentType(fileName) + CRLF;
} else {
statusLine = "HTTP/1.0 404 Not Found" + CRLF;
//contentTypeLine = "Content-type: " + "text/html" + CRLF;
entityBody = "<HTML>"
+ "<HEAD><TITLE>Not Found</TITLE></HEAD>"
+ "<BODY>Not Found</BODY></HTML>";
}
dos.writeBytes(statusLine);
dos.writeBytes(contentTypeLine);
dos.writeBytes(CRLF);
if (fileExists) {
sendBytes(fis, dos);
fis.close();
} else {
dos.writeBytes(entityBody);
}
}
br.close();
dos.close();
socket.close();
}
private void sendBytes(FileInputStream fis, DataOutputStream dos) throws IOException {
byte[] buffer = new byte[4096];
int bytes = 0;
while ((bytes = fis.read(buffer)) != -1) {
dos.write(buffer, 0, bytes);
}
}
private String contentType(String fileName) {
if (fileName.endsWith(".htm") || fileName.endsWith(".html")) {
return "text/html";
}
if (fileName.endsWith(".jpg") || fileName.endsWith(".jpeg")) {
return "image/jpeg";
}
if (fileName.endsWith(".gif")) {
return "image/gif";
}
if (fileName.endsWith(".txt")) {
return "text/plain";
}
if (fileName.endsWith(".pdf")) {
return "application/pdf";
}
return "application/octet-stream";
}
}
STACK TRACE
java.lang.NullPointerException
at java.io.DataOutputStream.writeBytes(DataOutputStream.java:274)
at HttpRequest.processRequest(HttpRequest.java:65)
at HttpRequest.run(HttpRequest.java:20)
at java.lang.Thread.run(Thread.java:724)

At least one issue is this code:
while ((headerLine = br.readLine()).length() != 0) {
System.out.println(headerLine);
}
BufferedReader will return null at the end of the stream, so calling .length() on a null object will yield a NullPointerException.
A more idiomatic way to write this is:
while ((headerLine = br.readLine()) != null && headerLine.length() != 0) {
System.out.println(headerLine);
}
...which takes advantage of short-circuit logic to not evaluate the second condition if the result of (headerLine = br.readLine()) is null.

It is happening because for some reason you have toggled comment on the following line:
//contentTypeLine = "Content-type: " + "text/html" + CRLF;
Untoggle it and you're good!

Open Stream and CancellationException causes Thread lock

I have a rather complex application that I'm trying to create for an android phone. I have a class that uses the Java Process Builder and some private classes to read from both the input and output streams.
At times when the IP I'm trying to ping does not respond the thread locks due to the process getting stuck, the executor service decides after 2 minutes to shutdown. This avoids the entire application locking but the two streams never close and the threads for the streams stay open.
Any idea how to kill the stream threads?
class StreamGobbler extends Thread {
InputStream is;
String type;
StreamGobbler(InputStream is, String type) {
this.is = is;
this.type = type;
}
public void run() {
InputStreamReader isr = new InputStreamReader(is);
try {
BufferedReader br = new BufferedReader(isr);
String line = null;
while ((line = br.readLine()) != null){
System.out.println(type + ">" + line);
}
} catch (IOException e) {
LogWriter.getInstance().writeToLogFile(e);
}finally{
try {
if(is != null){
is.close();
}
if(isr != null){
isr.close();
}
} catch (IOException e) {
LogWriter.getInstance().writeToLogFile(e);
}
}
}
public void kill() {
Thread.currentThread().interrupt();
}
}
public class PingRunner implements Callable<Double>{
private String pingVal;
private int exitVal;
private double laten;
private String ipAddress;
public PingRunner(String ipAddress) {
pingVal = "";
exitVal = -1;
laten = -1;
this.ipAddress = ipAddress;
}
#Override
public Double call() throws Exception {
List<String> commands = new ArrayList<String>();
commands.add("ping");
commands.add("-c");
commands.add("5");
commands.add(ipAddress);
try {
this.doCommand(commands);
} catch (IOException e) {
LogWriter.getInstance().writeToLogFile(e);
}
return laten;
}
private void doCommand(List<String> command) throws IOException{
ProcessBuilder pb = new ProcessBuilder(command);
Process process = pb.start();
// any error message?
StreamGobbler errorGobbler = new StreamGobbler(
process.getErrorStream(), "ERROR");
// any output?
OutputStreamGobbler outputGobbler = new OutputStreamGobbler(
process.getInputStream(), "OUTPUT");
// kick them off
errorGobbler.start();
outputGobbler.start();
// read the output from the command
try {
exitVal = process.waitFor();
//Sleep for 10 secs to try to clear the buffer
Thread.sleep(10000);
//pingVal = echo.toString();
if(exitVal == 0 && !pingVal.isEmpty()){
//System.out.println("PING STATS: "+pingVal);
try{
pingVal = pingVal.substring(pingVal.lastIndexOf("rtt min/avg/max/mdev"));
pingVal = pingVal.substring(23);
pingVal = pingVal.substring(pingVal.indexOf("/")+1);
laten = Double.parseDouble(pingVal.substring(0,pingVal.indexOf("/")));
}catch (IndexOutOfBoundsException e){
System.out.println("PING VAL: "+ pingVal);
LogWriter.getInstance().writeToLogFile(e);
}
}
} catch (InterruptedException e) {
LogWriter.getInstance().writeToLogFile(e);
errorGobbler.kill();
outputGobbler.kill();
}finally{
errorGobbler = null;
outputGobbler = null;
}
System.out.println("ExitValue: " + exitVal);
}
In my main class I have this method:
protected void ping() {
laten = -1;
serverIP = serverIPs.get(testIndex % 3);
PingRunner pRunner = new PingRunner(serverIP);
Set<Callable<Double>> runner = new HashSet<Callable<Double>>();
runner.add(pRunner);
ExecutorService executor = Executors.newSingleThreadExecutor();
try {
laten = executor.submit(pRunner).get(2, TimeUnit.MINUTES);
executor.shutdown();
} catch (InterruptedException e) {
LogWriter.getInstance().writeToLogFile(e);
} catch (ExecutionException e) {
LogWriter.getInstance().writeToLogFile(e);
} catch (CancellationException e) {
pRunner.kill();
executor.shutdown();
LogWriter.getInstance().writeToLogFile(e);
LogWriter.getInstance().writeToLogFile(
"ERROR: Unable to ping server: " + serverIP);
} catch (TimeoutException e) {
pRunner.kill();
executor.shutdown();
LogWriter.getInstance().writeToLogFile(e);
LogWriter.getInstance().writeToLogFile(
"ERROR: Unable to ping server: " + serverIP);
} finally {
executor = null;
System.gc();
}

Any idea how to kill the stream threads?
Not sure what is going on but one bug I see is:
public void kill() {
Thread.currentThread().interrupt();
}
That is interrupting the caller thread, not the gobbler thread. That should be:
public void kill() {
// kill the gobbler thread
interrupt();
}
This is true since the StreamGobbler extends Thread. As always, it is recommended that you implements Runnable and then have a private Thread field if necessary. Then you would do something like thread.interrupt();.
Also, you are not closing your streams correctly. Typically, when I wrap one stream in another, I set the wrapped stream to be null. Also, you are not closing the br BufferedReader. The code should be:
InputStreamReader isr = new InputStreamReader(is);
is = null;
BufferedReader br = null;
try {
br = new BufferedReader(isr);
isr = null;
String line = null;
...
} finally {
// IOException catches not listed
if(br != null){
br.close();
}
if(isr != null){
isr.close();
}
if(is != null){
is.close();
}
}
I'm a big fan of the org.apache.commons.io.IOUtils package that has the closeQuietly(...) method that turns the finally block into:
IOUtils.closeQuietly(br);
IOUtils.closeQuietly(isr);
IOUtils.closeQuietly(is);