Using substring and charAt

I'm having trouble, whenever I try to read from a URL with this code:

Code:java

URL url = new URL("[URL]https://raw.github.com/keybordpiano459/Newspaper/master/version.txt[/URL]");
BufferedReader br = new BufferedReader(new InputStreamReader(url.openStream()));
String string;
while ((string = br.readLine()) != null) {
    String line = br.readLine();
    if (line.charAt(0) == '#') return;
    if (line.substring(0, 4).equals(currentVersion + ": "))
        plugin.updatemsg = line.substring(5);
    log.info(plugin.updatemsg);
}
br.close();

I get this stacktrace:

Code:

08:50:18 [SEVERE] Error occurred while enabling Newspaper v1.3 (Is it up to date?)
java.lang.StringIndexOutOfBoundsException: String index out of range: 0
    at java.lang.String.charAt(String.java:658)
    at me.KeybordPiano459.Newspaper.UpdateChecker.startUpdateCheck(UpdateChecker.java:29)
    at me.KeybordPiano459.Newspaper.Newspaper.onEnable(Newspaper.java:35)
    at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:217)
    at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:457)
    at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:381)
    at org.bukkit.craftbukkit.v1_4_R1.CraftServer.loadPlugin(CraftServer.java:282)
    at org.bukkit.craftbukkit.v1_4_R1.CraftServer.enablePlugins(CraftServer.java:264)
    at net.minecraft.server.v1_4_R1.MinecraftServer.j(MinecraftServer.java:321)
    at net.minecraft.server.v1_4_R1.MinecraftServer.e(MinecraftServer.java:300)
    at net.minecraft.server.v1_4_R1.MinecraftServer.a(MinecraftServer.java:259)
    at net.minecraft.server.v1_4_R1.DedicatedServer.init(DedicatedServer.java:149)
    at net.minecraft.server.v1_4_R1.MinecraftServer.run(MinecraftServer.java:399)
    at net.minecraft.server.v1_4_R1.ThreadServerApplication.run(SourceFile:849)

Any idea what's wrong? I'm pretty sure that when using charAt and substring, you're supposed to start at 0.

Btw, there aren't supposed to be [.url] tags in the first syntax thingy.

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

it seems there is n empty line inside the file, check if the string is empty by using .isempty

 

I already try checking if the line is null or not, wouldn't that do it?

By changing the while to loop to this, it didn't make a stacktrace, however, it doesn't print anything past "Checking for a new version..."

Code:java

while (br.readLine() != null && !br.readLine().isEmpty()) {

When I replace && with ||, it just makes the stacktrace again =/

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

Code:java

 
while ((string = br.readLine()) != null) {
    String line = br.readLine();
 

I think that should be

Code:java

 
while ((string = br.readLine()) != null) {
    String line = string;
 

 

ferrybig
Now I have

Code:java

String string;
while ((string = br.readLine()) != null) {
    String line = string;

And all it does is print "Checking for a new update..."
Why doesn't this work?

Code:java

while (br.readLine() != null || !br.readLine().isEmpty()) {
    String line = br.readLine();

 

the lower line read 3 different lines, the top line reuses the same same, so the cursor only advances 1 line eacdh operation

 

Well ferrybig
I did some debugging, and seems that the while loop only prints once, and I think that's because it thinks the second line is null. If you goto the URL, it is, so I'm going to try to fix it

ferrybig
It seems like the blank line wasn't the case, you can look at the edited .txt file now, and the while loop still only prints once. There's no blank line in the file anymore.

Anyhow, I fixed it on my own. If anyone is curious how, here's the code:

Code:java

URL url = new URL("[URL]https://raw.github.com/keybordpiano459/Newspaper/master/version.txt[/URL]");
BufferedReader br = new BufferedReader(new InputStreamReader(url.openStream()));
String str;
while ((str = br.readLine()) != null) {
    String line = str;
    if (line.charAt(0) == '#');
    if (line.charAt(0) == '1' && line.charAt(2) == '3') {
        plugin.updatemsg = line.substring(5);
        log.info(plugin.updatemsg);
    }
}
br.close();

EDIT by Moderator: merged posts, please use the edit button instead of double posting.