diff --git a/parquet-column/src/main/java/org/apache/parquet/filter2/predicate/Operators.java b/parquet-column/src/main/java/org/apache/parquet/filter2/predicate/Operators.java
index 32b443091b..eca0f6700a 100644
--- a/parquet-column/src/main/java/org/apache/parquet/filter2/predicate/Operators.java
+++ b/parquet-column/src/main/java/org/apache/parquet/filter2/predicate/Operators.java
@@ -19,6 +19,7 @@
 package org.apache.parquet.filter2.predicate;
 
 import java.io.Serializable;
+import java.util.Locale;
 
 import org.apache.parquet.hadoop.metadata.ColumnPath;
 import org.apache.parquet.io.api.Binary;
@@ -129,7 +130,7 @@ protected ColumnFilterPredicate(Column<T> column, T value) {
       // null in their own constructors.
       this.value = value;
 
-      String name = getClass().getSimpleName().toLowerCase();
+      String name = getClass().getSimpleName().toLowerCase(Locale.ENGLISH);
       this.toString = name + "(" + column.getColumnPath().toDotString() + ", " + value + ")";
     }
 
@@ -258,7 +259,7 @@ private static abstract class BinaryLogicalFilterPredicate implements FilterPred
     protected BinaryLogicalFilterPredicate(FilterPredicate left, FilterPredicate right) {
       this.left = checkNotNull(left, "left");
       this.right = checkNotNull(right, "right");
-      String name = getClass().getSimpleName().toLowerCase();
+      String name = getClass().getSimpleName().toLowerCase(Locale.ENGLISH);
       this.toString = name + "(" + left + ", " + right + ")";
     }
 
@@ -386,7 +387,7 @@ public static final class UserDefinedByClass<T extends Comparable<T>, U extends
     UserDefinedByClass(Column<T> column, Class<U> udpClass) {
       super(column);
       this.udpClass = checkNotNull(udpClass, "udpClass");
-      String name = getClass().getSimpleName().toLowerCase();
+      String name = getClass().getSimpleName().toLowerCase(Locale.ENGLISH);
       this.toString = name + "(" + column.getColumnPath().toDotString() + ", " + udpClass.getName() + ")";
 
       // defensively try to instantiate the class early to make sure that it's possible
@@ -442,7 +443,7 @@ public static final class UserDefinedByInstance<T extends Comparable<T>, U exten
     UserDefinedByInstance(Column<T> column, U udpInstance) {
       super(column);
       this.udpInstance = checkNotNull(udpInstance, "udpInstance");
-      String name = getClass().getSimpleName().toLowerCase();
+      String name = getClass().getSimpleName().toLowerCase(Locale.ENGLISH);
       this.toString = name + "(" + column.getColumnPath().toDotString() + ", " + udpInstance + ")";
     }
 
diff --git a/parquet-column/src/main/java/org/apache/parquet/schema/GroupType.java b/parquet-column/src/main/java/org/apache/parquet/schema/GroupType.java
index 027fbc0dfc..f8404a1cd0 100644
--- a/parquet-column/src/main/java/org/apache/parquet/schema/GroupType.java
+++ b/parquet-column/src/main/java/org/apache/parquet/schema/GroupType.java
@@ -24,6 +24,7 @@
 import java.util.Arrays;
 import java.util.HashMap;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 
 import org.apache.parquet.io.InvalidRecordException;
@@ -208,7 +209,7 @@ void membersDisplayString(StringBuilder sb, String indent) {
   @Override
   public void writeToStringBuilder(StringBuilder sb, String indent) {
     sb.append(indent)
-        .append(getRepetition().name().toLowerCase())
+        .append(getRepetition().name().toLowerCase(Locale.ENGLISH))
         .append(" group ")
         .append(getName())
         .append(getOriginalType() == null ? "" : " (" + getOriginalType() +")")
diff --git a/parquet-column/src/main/java/org/apache/parquet/schema/MessageTypeParser.java b/parquet-column/src/main/java/org/apache/parquet/schema/MessageTypeParser.java
index 49813987df..b7274c2c5c 100644
--- a/parquet-column/src/main/java/org/apache/parquet/schema/MessageTypeParser.java
+++ b/parquet-column/src/main/java/org/apache/parquet/schema/MessageTypeParser.java
@@ -19,6 +19,7 @@
 package org.apache.parquet.schema;
 
 import java.util.Arrays;
+import java.util.Locale;
 import java.util.StringTokenizer;
 
 import org.apache.parquet.Log;
@@ -195,7 +196,7 @@ private static void addPrimitiveType(Tokenizer st, PrimitiveTypeName type, Repet
 
   private static PrimitiveTypeName asPrimitive(String t, Tokenizer st) {
     try {
-      return PrimitiveTypeName.valueOf(t.toUpperCase());
+      return PrimitiveTypeName.valueOf(t.toUpperCase(Locale.ENGLISH));
     } catch (IllegalArgumentException e) {
       throw new IllegalArgumentException("expected one of " + Arrays.toString(PrimitiveTypeName.values())  +" got " + t + " at " + st.getLocationString(), e);
     }
@@ -203,7 +204,7 @@ private static PrimitiveTypeName asPrimitive(String t, Tokenizer st) {
 
   private static Repetition asRepetition(String t, Tokenizer st) {
     try {
-      return Repetition.valueOf(t.toUpperCase());
+      return Repetition.valueOf(t.toUpperCase(Locale.ENGLISH));
     } catch (IllegalArgumentException e) {
       throw new IllegalArgumentException("expected one of " + Arrays.toString(Repetition.values())  +" got " + t + " at " + st.getLocationString(), e);
     }
diff --git a/parquet-column/src/main/java/org/apache/parquet/schema/PrimitiveType.java b/parquet-column/src/main/java/org/apache/parquet/schema/PrimitiveType.java
index 5c6e460cb7..503e048685 100644
--- a/parquet-column/src/main/java/org/apache/parquet/schema/PrimitiveType.java
+++ b/parquet-column/src/main/java/org/apache/parquet/schema/PrimitiveType.java
@@ -20,6 +20,7 @@
 
 import java.util.Arrays;
 import java.util.List;
+import java.util.Locale;
 
 import org.apache.parquet.column.ColumnReader;
 import org.apache.parquet.io.InvalidRecordException;
@@ -394,7 +395,7 @@ public void accept(TypeVisitor visitor) {
   @Override
   public void writeToStringBuilder(StringBuilder sb, String indent) {
     sb.append(indent)
-        .append(getRepetition().name().toLowerCase())
+        .append(getRepetition().name().toLowerCase(Locale.ENGLISH))
         .append(" ")
         .append(primitive.name().toLowerCase());
     if (primitive == PrimitiveTypeName.FIXED_LEN_BYTE_ARRAY) {
diff --git a/parquet-hadoop/src/main/java/org/apache/parquet/hadoop/metadata/CompressionCodecName.java b/parquet-hadoop/src/main/java/org/apache/parquet/hadoop/metadata/CompressionCodecName.java
index 558bea7bf3..d03d280128 100644
--- a/parquet-hadoop/src/main/java/org/apache/parquet/hadoop/metadata/CompressionCodecName.java
+++ b/parquet-hadoop/src/main/java/org/apache/parquet/hadoop/metadata/CompressionCodecName.java
@@ -21,6 +21,8 @@
 import org.apache.parquet.format.CompressionCodec;
 import org.apache.parquet.hadoop.codec.CompressionCodecNotSupportedException;
 
+import java.util.Locale;
+
 public enum CompressionCodecName {
   UNCOMPRESSED(null, CompressionCodec.UNCOMPRESSED, ""),
   SNAPPY("org.apache.parquet.hadoop.codec.SnappyCodec", CompressionCodec.SNAPPY, ".snappy"),
@@ -31,7 +33,7 @@ public static CompressionCodecName fromConf(String name) {
      if (name == null) {
        return UNCOMPRESSED;
      }
-     return valueOf(name.toUpperCase());
+     return valueOf(name.toUpperCase(Locale.ENGLISH));
   }
 
   public static CompressionCodecName fromCompressionCodec(Class<?> clazz) {