Summary

This CSR covers an update to the hexadecimal floating point conversion 'a' zero padding to fix a bug where an extra zero would be padded in the presence of a sign flag (+) or a leading space flag (' '). The change accounts for these flags when zero-padding.

Problem

The formatter does not account for a sign flag or leading sign space flag when formatting a hex float conversion with a zero-padding flag. This creates zero paddings with one too many zeros.

Solution

If a zero-padding flag is present, we check if a leading space or plus flag is present. If one of those flags is present, we shorten the zero padding length by an additional character.

Specification

diff --git a/src/java.base/share/classes/java/util/Formatter.java b/src/java.base/share/classes/java/util/Formatter.java
index c4dc4c0b85d..17ab55ddd80 100644
--- a/src/java.base/share/classes/java/util/Formatter.java
+++ b/src/java.base/share/classes/java/util/Formatter.java
@@ -3548,7 +3548,12 @@ public final class Formatter implements Closeable, Flushable {
                 sb.append(upper ? "0X" : "0x");

                 if (f.contains(Flags.ZERO_PAD)) {
-                    trailingZeros(sb, width - s.length() - 2);
+                    int leadingCharacters = 2;
+                    if(f.contains(Flags.LEADING_SPACE) ||
+                            f.contains(Flags.PLUS) || neg) {
+                        leadingCharacters = 3;
+                    }
+                    trailingZeros(sb, width - s.length() - leadingCharacters);
                 }