8333456: CompactNumberFormat integer parsing fails when string has no suffix

src/java.base/share/classes/java/text/CompactNumberFormat.java

@@ -1681,7 +1681,7 @@ public Number parse(String text, ParsePosition pos) {
         // If parse integer only is true and the parsing is broken at
         // decimal point, then pass/ignore all digits and move pointer
         // at the start of suffix, to process the suffix part
-        if (isParseIntegerOnly()
+        if (isParseIntegerOnly() && position < text.length()
                 && text.charAt(position) == symbols.getDecimalSeparator()) {
             position++; // Pass decimal character
             for (; position < text.length(); ++position) {

test/jdk/java/text/Format/NumberFormat/Bug8333456.java

@@ -0,0 +1,91 @@
+/*
+ * Copyright (c) 2004, 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8333456
+ * @summary Make sure that CompactNumberFormat integer parsing doesn't fail
+ * when there is no suffix.
+ * @run junit Bug8333456
+ */
+
+import java.text.CompactNumberFormat;
+import java.text.NumberFormat;
+import java.text.ParsePosition;
+import java.util.Locale;
+import java.util.stream.Stream;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.condition.EnabledIfSystemProperty;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class Bug8333456 {
+
+    private static final CompactNumberFormat cmpctFmt =
+            (CompactNumberFormat) NumberFormat.getCompactNumberInstance(Locale.US,
+                    NumberFormat.Style.SHORT);
+
+    // No compact suffixes
+    private static final Stream<Arguments> compactValidNoSuffixParseStrings() {
+        return Stream.of(
+                Arguments.of("5", 5),
+                Arguments.of("50", 50),
+                Arguments.of("50.", 50),
+                Arguments.of("5,000", 5000),
+                Arguments.of("5,000.", 5000),
+                Arguments.of("5,000.00", 5000)
+        );
+    }
+
+    // 8333456: Parse values with no compact suffix -> which allows parsing to iterate
+    // position to the same value as string length which throws
+    // StringIndexOutOfBoundsException upon charAt invocation
+    @ParameterizedTest
+    @MethodSource("compactValidNoSuffixParseStrings")
+    @EnabledIfSystemProperty(named = "user.language", matches = "en")
+    public void compactFmtSuccessParseIntOnlyTest(String toParse, double expectedValue) {
+        cmpctFmt.setParseIntegerOnly(true);
+        cmpctFmt.setGroupingUsed(true);
+        assertEquals(expectedValue, successParse(cmpctFmt, toParse, toParse.length()));
+        cmpctFmt.setParseIntegerOnly(false);
+    }
+
+    // Method is used when a String should parse successfully. This does not indicate
+    // that the entire String was used, however. The index and errorIndex values
+    // should be as expected.
+    private double successParse(NumberFormat fmt, String toParse, int expectedIndex) {
+        Number parsedValue = assertDoesNotThrow(() -> fmt.parse(toParse));
+        ParsePosition pp = new ParsePosition(0);
+        assertDoesNotThrow(() -> fmt.parse(toParse, pp));
+        assertEquals(-1, pp.getErrorIndex(),
+                "ParsePosition ErrorIndex is not in correct location");
+        assertEquals(expectedIndex, pp.getIndex(),
+                "ParsePosition Index is not in correct location");
+        return parsedValue.doubleValue();
+    }
+}