FULL PRODUCT VERSION :
java version "1.8.0_25"
Java(TM) SE Runtime Environment (build 1.8.0_25-b18)
Java HotSpot(TM) Client VM (build 25.25-b02, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Wersja 6.1.7601]

A DESCRIPTION OF THE PROBLEM :
Acording to documentation multi parameter java.net.URI constructors should escape any illegal uri characters. But this seems not to be the case for [] (square brackets) in path.

Try to run the following code:

import java.net.URI;

public class BugReproduction {
   public static void main(String[] args) throws Exception {
new URI("file","/temp/a[1].txt", null);
   }
}

According to documentation it should be working fine, all illegal characters should be escaped/quoted. But instead it throws:

Exception in thread "main" java.net.URISyntaxException: Illegal character in path at index 11: file:/temp/[1].txt
at java.net.URI$Parser.fail(URI.java:2829)
at java.net.URI$Parser.checkChars(URI.java:3002)
at java.net.URI$Parser.parseHierarchical(URI.java:3086)
at java.net.URI$Parser.parse(URI.java:3034)
at java.net.URI.<init>(URI.java:824)


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Try to run the following code:

import java.net.URI;

public class BugReproduction {
   public static void main(String[] args) throws Exception {
new URI("file","/temp/a[1].txt", null);
   }
}

According to documentation it should be working fine, all illegal characters should be escaped/quoted. But instead it throws:

Exception in thread "main" java.net.URISyntaxException: Illegal character in path at index 11: file:/temp/[1].txt
at java.net.URI$Parser.fail(URI.java:2829)
at java.net.URI$Parser.checkChars(URI.java:3002)
at java.net.URI$Parser.parseHierarchical(URI.java:3086)
at java.net.URI$Parser.parse(URI.java:3034)
at java.net.URI.<init>(URI.java:824)


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
No exception is thrown
ACTUAL -
Exception in thread "main" java.net.URISyntaxException: Illegal character in path at index 11: file:/temp/[1].txt
at java.net.URI$Parser.fail(URI.java:2829)
at java.net.URI$Parser.checkChars(URI.java:3002)
at java.net.URI$Parser.parseHierarchical(URI.java:3086)
at java.net.URI$Parser.parse(URI.java:3034)
at java.net.URI.<init>(URI.java:824)


ERROR MESSAGES/STACK TRACES THAT OCCUR :
Exception in thread "main" java.net.URISyntaxException: Illegal character in path at index 11: file:/temp/[1].txt
at java.net.URI$Parser.fail(URI.java:2829)
at java.net.URI$Parser.checkChars(URI.java:3002)
at java.net.URI$Parser.parseHierarchical(URI.java:3086)
at java.net.URI$Parser.parse(URI.java:3034)
at java.net.URI.<init>(URI.java:824)


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.net.URI;

public class BugReproduction {
   public static void main(String[] args) throws Exception {
new URI("file","/temp/a[1].txt", null);
   }
}

---------- END SOURCE ----------