diff --git a/icu4j/main/classes/core/src/com/ibm/icu/impl/number/LocalizedNumberFormatterAsFormat.java b/icu4j/main/classes/core/src/com/ibm/icu/impl/number/LocalizedNumberFormatterAsFormat.java
index 2a034e96052..cd1ee791149 100644
--- a/icu4j/main/classes/core/src/com/ibm/icu/impl/number/LocalizedNumberFormatterAsFormat.java
+++ b/icu4j/main/classes/core/src/com/ibm/icu/impl/number/LocalizedNumberFormatterAsFormat.java
@@ -23,6 +23,8 @@ import com.ibm.icu.util.ULocale;
  */
 public class LocalizedNumberFormatterAsFormat extends Format {
 
+    private static final long serialVersionUID = 1L;
+
     private final transient LocalizedNumberFormatter formatter;
 
     // Even though the locale is inside the LocalizedNumberFormatter, we have to keep it here, too, because
@@ -114,6 +116,8 @@ public class LocalizedNumberFormatterAsFormat extends Format {
     }
 
     static class Proxy implements Externalizable {
+        private static final long serialVersionUID = 1L;
+
         String languageTag;
         String skeleton;
 
diff --git a/icu4j/main/classes/core/src/com/ibm/icu/impl/number/parse/SeriesMatcher.java b/icu4j/main/classes/core/src/com/ibm/icu/impl/number/parse/SeriesMatcher.java
index 466be0e648c..6d2147f6589 100644
--- a/icu4j/main/classes/core/src/com/ibm/icu/impl/number/parse/SeriesMatcher.java
+++ b/icu4j/main/classes/core/src/com/ibm/icu/impl/number/parse/SeriesMatcher.java
@@ -12,7 +12,6 @@ import com.ibm.icu.impl.StringSegment;
  * matchers in the series succeed. Performs greedy matches within the context of the series.
  *
  * @author sffc
- * @see AnyMatcher
  */
 public class SeriesMatcher implements NumberParseMatcher {
 
diff --git a/icu4j/main/classes/core/src/com/ibm/icu/number/CurrencyRounder.java b/icu4j/main/classes/core/src/com/ibm/icu/number/CurrencyRounder.java
index 44740512667..aef07f6434c 100644
--- a/icu4j/main/classes/core/src/com/ibm/icu/number/CurrencyRounder.java
+++ b/icu4j/main/classes/core/src/com/ibm/icu/number/CurrencyRounder.java
@@ -8,4 +8,8 @@ package com.ibm.icu.number;
  */
 @Deprecated
 public abstract class CurrencyRounder extends CurrencyPrecision {
+    // package private constructor just for blocking
+    // java compiler to generate public no-arg constructor.
+    CurrencyRounder() {
+    }
 }
\ No newline at end of file
diff --git a/icu4j/main/classes/core/src/com/ibm/icu/number/FormattedNumber.java b/icu4j/main/classes/core/src/com/ibm/icu/number/FormattedNumber.java
index 965f5629b5e..34030048ce4 100644
--- a/icu4j/main/classes/core/src/com/ibm/icu/number/FormattedNumber.java
+++ b/icu4j/main/classes/core/src/com/ibm/icu/number/FormattedNumber.java
@@ -105,7 +105,6 @@ public class FormattedNumber {
      * <p>
      * If a field occurs just once, calling this method will find that occurrence and return it. If a
      * field occurs multiple times, this method may be called repeatedly with the following pattern:
-     * <p>
      *
      * <pre>
      * FieldPosition fpos = new FieldPosition(NumberFormat.Field.GROUPING_SEPARATOR);
diff --git a/icu4j/main/classes/core/src/com/ibm/icu/number/FractionRounder.java b/icu4j/main/classes/core/src/com/ibm/icu/number/FractionRounder.java
index 56e91503070..5fd1a6e7b30 100644
--- a/icu4j/main/classes/core/src/com/ibm/icu/number/FractionRounder.java
+++ b/icu4j/main/classes/core/src/com/ibm/icu/number/FractionRounder.java
@@ -8,4 +8,8 @@ package com.ibm.icu.number;
  */
 @Deprecated
 public abstract class FractionRounder extends FractionPrecision {
+    // package private constructor just for blocking
+    // java compiler to generate public no-arg constructor.
+    FractionRounder() {
+    }
 }
\ No newline at end of file
diff --git a/icu4j/main/classes/core/src/com/ibm/icu/number/Rounder.java b/icu4j/main/classes/core/src/com/ibm/icu/number/Rounder.java
index f9db169e364..fa42942825a 100644
--- a/icu4j/main/classes/core/src/com/ibm/icu/number/Rounder.java
+++ b/icu4j/main/classes/core/src/com/ibm/icu/number/Rounder.java
@@ -8,4 +8,8 @@ package com.ibm.icu.number;
  */
 @Deprecated
 public abstract class Rounder extends Precision {
+    // package private constructor just for blocking
+    // java compiler to generate public no-arg constructor.
+    Rounder() {
+    }
 }
diff --git a/icu4j/main/classes/core/src/com/ibm/icu/number/Scale.java b/icu4j/main/classes/core/src/com/ibm/icu/number/Scale.java
index 2952e885a11..ef3e3868fda 100644
--- a/icu4j/main/classes/core/src/com/ibm/icu/number/Scale.java
+++ b/icu4j/main/classes/core/src/com/ibm/icu/number/Scale.java
@@ -74,7 +74,6 @@ public class Scale {
 
     /**
      * Multiply numbers by 100 before formatting. Useful for combining with a percent unit:
-     * <p>
      *
      * <pre>
      * NumberFormatter.with().unit(NoUnit.PERCENT).multiplier(Multiplier.powerOfTen(2))
diff --git a/icu4j/main/classes/core/src/com/ibm/icu/text/Edits.java b/icu4j/main/classes/core/src/com/ibm/icu/text/Edits.java
index d8394321e57..1e992f7fa16 100644
--- a/icu4j/main/classes/core/src/com/ibm/icu/text/Edits.java
+++ b/icu4j/main/classes/core/src/com/ibm/icu/text/Edits.java
@@ -19,7 +19,6 @@ import java.util.Arrays;
  * {@link Edits.Iterator} can be used for queries.
  * <p>
  * There are four flavors of Edits.Iterator:
- * <p>
  * <ul>
  * <li>{@link #getFineIterator()} retains full granularity of change edits.
  * <li>{@link #getFineChangesIterator()} retains full granularity of change edits, and when calling
@@ -822,7 +821,10 @@ public final class Edits {
         /**
          * A string representation of the current edit represented by the iterator for debugging. You
          * should not depend on the contents of the return string.
+         * @internal
+         * @deprecated This API is ICU internal only.
          */
+        @Deprecated
         @Override
         public String toString() {
             StringBuilder sb = new StringBuilder();