RFR: JDK-6956385: URLConnection.getLastModified() leaks file handles for jar:file and file: URLs [v3]

[Daniel Fuchs]

On Mon, 22 May 2023 17:49:12 GMT, Jesse Glick <duke at openjdk.org> wrote:

>> This patch appears to be work and may be preferable to what is currently proposed:
>> 
>> 
>> diff --git src/java.base/share/classes/sun/net/www/protocol/file/FileURLConnection.java src/java.base/share/classes/sun/net/www/protocol/file/FileURLConnection.java
>> index a9ce7cee9a1..55783474c22 100644
>> --- src/java.base/share/classes/sun/net/www/protocol/file/FileURLConnection.java
>> +++ src/java.base/share/classes/sun/net/www/protocol/file/FileURLConnection.java
>> @@ -53,7 +53,6 @@ public class FileURLConnection extends URLConnection {
>>      File file;
>>      String filename;
>>      boolean isDirectory = false;
>> -    boolean exists = false;
>>      List<String> files;
>>  
>>      long length = -1;
>> @@ -93,16 +92,12 @@ public class FileURLConnection extends URLConnection {
>>      private boolean initializedHeaders = false;
>>  
>>      private void initializeHeaders() {
>> -        try {
>> -            connect();
>> -            exists = file.exists();
>> -        } catch (IOException e) {
>> -        }
>> -        if (!initializedHeaders || !exists) {
>> +        if (!initializedHeaders || !file.exists()) {
>>              length = file.length();
>>              lastModified = file.lastModified();
>> +            filename = file.toString();
>>  
>> -            if (!isDirectory) {
>> +            if (!file.isDirectory()) {
>>                  FileNameMap map = java.net.URLConnection.getFileNameMap();
>>                  contentType = map.getContentTypeFor(filename);
>>                  if (contentType != null) {
>> @@ -131,17 +126,17 @@ public class FileURLConnection extends URLConnection {
>>  
>>      public Map<String,List<String>> getHeaderFields() {
>>          initializeHeaders();
>> -        return super.getHeaderFields();
>> +        return properties.getHeaders();
>>      }
>>  
>>      public String getHeaderField(String name) {
>>          initializeHeaders();
>> -        return super.getHeaderField(name);
>> +        return properties.findValue(name);
>>      }
>>  
>>      public String getHeaderField(int n) {
>>          initializeHeaders();
>> -        return super.getHeaderField(n);
>> +        return properties.getKey(n);
>>      }
>>  
>>      public int getContentLength() {
>
>> has this comment
> 
> Interesting. And yet that does not appear to be true in `master`: `getContentType` and `getContentLength` will return whatever was in effect at the time `initializeHeaders()` was first called, which may have been before any explicit call to `connect()`, or hours after an explicit call.

Ah! It's true only if the first time connect is called, it's implicitly by `initializeHeaders()` (sigh)...

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PR Review Comment: https://git.openjdk.org/jdk/pull/12871#discussion_r1200844827