Use char-append instead of String-append

ebean-api/src/main/java/io/ebean/StdOperators.java

@@ -77,9 +77,9 @@ public final class StdOperators {
     StringBuilder expression = new StringBuilder(50);
     expression.append("concat(").append(property.toString());
     for (Object value : values) {
-      expression.append(",").append(sqlConcatString(value));
+      expression.append(',').append(sqlConcatString(value));
     }
-    expression.append(")");
+    expression.append(')');
     return Property.of(expression.toString());
   }
 

ebean-api/src/main/java/io/ebean/cache/TenantAwareKey.java

@@ -69,7 +69,7 @@ public class TenantAwareKey {
     public String toString() {
       StringBuilder sb = new StringBuilder(key.toString());
       if (tenantId != null) {
-        sb.append(":").append(tenantId);
+        sb.append(':').append(tenantId);
       }
       return sb.toString();
     }

ebean-api/src/main/java/io/ebean/config/AbstractNamingConvention.java

@@ -228,7 +228,7 @@ public abstract class AbstractNamingConvention implements NamingConvention {
   public TableName getM2MJoinTableName(TableName lhsTable, TableName rhsTable) {
     StringBuilder buffer = new StringBuilder();
     buffer.append(unQuote(lhsTable.getName()));
-    buffer.append("_");
+    buffer.append('_');
 
     String rhsTableName = unQuote(rhsTable.getName());
     if (rhsTableName.indexOf('_') < rhsPrefixLength) {
@@ -271,10 +271,10 @@ public abstract class AbstractNamingConvention implements NamingConvention {
   public String getTableName(String catalog, String schema, String name) {
     StringBuilder sb = new StringBuilder();
     if (!isNull(catalog)) {
-      sb.append(quoteIdentifiers(catalog)).append(".");
+      sb.append(quoteIdentifiers(catalog)).append('.');
     }
     if (!isNull(schema)) {
-      sb.append(quoteIdentifiers(schema)).append(".");
+      sb.append(quoteIdentifiers(schema)).append('.');
     }
     return sb.append(quoteIdentifiers(name)).toString();
   }

ebean-api/src/main/java/io/ebean/config/DbConstraintNaming.java

@@ -140,7 +140,7 @@ public class DbConstraintNaming {
     StringBuilder sb = new StringBuilder();
     for (int i = 0; i < columns.length; i++) {
       if (i > 0) {
-        sb.append("_");
+        sb.append('_');
       }
       sb.append(normaliseColumn(columns[i]));
     }

ebean-api/src/main/java/io/ebean/config/TableName.java

@@ -117,12 +117,12 @@ public final class TableName {
     // Add schema
     if (schema != null) {
       if (buffer.length() > 0) {
-        buffer.append(".");
+        buffer.append('.');
       }
       buffer.append(schema);
     }
     if (buffer.length() > 0) {
-      buffer.append(".");
+      buffer.append('.');
     }
     return buffer.append(name).toString();
   }

ebean-api/src/main/java/io/ebean/meta/MetricsAsJson.java

@@ -118,28 +118,28 @@ final class MetricsAsJson implements ServerMetricsAsJson {
 
   private void objStart() throws IOException {
     objKeyCounter = 0;
-    writer.append("{");
+    writer.append('{');
   }
 
   private void objEnd() throws IOException {
-    writer.append("}");
+    writer.append('}');
   }
 
   private void listStart() throws IOException {
     listCounter = 0;
-    writer.append("[");
+    writer.append('[');
     writer.append(newLine);
   }
 
   private void listEnd() throws IOException {
-    writer.append("]");
+    writer.append(']');
   }
 
   private void key(String key) throws IOException {
     if (objKeyCounter++ > 0) {
       writer.append(", ");
     }
-    writer.append("\"").append(key).append("\":");
+    writer.append('"').append(key).append("\":");
   }
 
   private void val(long count) throws IOException {
@@ -147,12 +147,12 @@ final class MetricsAsJson implements ServerMetricsAsJson {
   }
 
   private void val(String val) throws IOException {
-    writer.append("\"").append(val).append("\"");
+    writer.append('"').append(val).append('"');
   }
 
   private void metricStart(MetaMetric metric) throws IOException {
     if (listCounter++ > 0) {
-      writer.append(",").append(newLine);
+      writer.append(',').append(newLine);
     }
     objStart();
     key("name");

ebean-api/src/main/java/io/ebean/text/PathProperties.java

@@ -205,7 +205,7 @@ public class PathProperties implements FetchPath {
         sb.append(it.next());
         hasNext = it.hasNext();
         if (hasNext) {
-          sb.append(",");
+          sb.append(',');
         }
       }
       return sb.toString();

ebean-api/src/main/java/io/ebean/util/CamelCaseHelper.java

@@ -25,14 +25,14 @@ public final class CamelCaseHelper {
         lastUpper = i;
       } else if (Character.isDigit(c)) {
         if (i > lastUpper + 1 && !digitsCompressed) {
-          sb.append("_");
+          sb.append('_');
           lastUpper = i;
         }
         sb.append(c);
 
       } else if (Character.isUpperCase(c)) {
         if (i > lastUpper + 1) {
-          sb.append("_");
+          sb.append('_');
         }
         sb.append(Character.toLowerCase(c));
         lastUpper = i;