diff --git a/exercises/concept/booking-up-for-beauty/.meta/src/reference/java/AppointmentScheduler.java b/exercises/concept/booking-up-for-beauty/.meta/src/reference/java/AppointmentScheduler.java
index 3882b4db4..9e8915108 100644
--- a/exercises/concept/booking-up-for-beauty/.meta/src/reference/java/AppointmentScheduler.java
+++ b/exercises/concept/booking-up-for-beauty/.meta/src/reference/java/AppointmentScheduler.java
@@ -23,7 +23,7 @@ public boolean isAfternoonAppointment(LocalDateTime appointmentDate) {
 
     public String getDescription(LocalDateTime appointmentDate) {
         var formatter = DateTimeFormatter.ofPattern("EEEE, MMMM d, yyyy, 'at' h:mm a", Locale.ENGLISH);
-        return String.format("You have an appointment on %s.", formatter.format(appointmentDate));
+        return "You have an appointment on " + formatter.format(appointmentDate) + ".";
     }
 
     public LocalDate getAnniversaryDate() {
diff --git a/exercises/concept/calculator-conundrum/.meta/src/reference/java/CalculatorConundrum.java b/exercises/concept/calculator-conundrum/.meta/src/reference/java/CalculatorConundrum.java
index 4728a29b3..fb409cc71 100644
--- a/exercises/concept/calculator-conundrum/.meta/src/reference/java/CalculatorConundrum.java
+++ b/exercises/concept/calculator-conundrum/.meta/src/reference/java/CalculatorConundrum.java
@@ -19,9 +19,9 @@ public String calculate(int operand1, int operand2, String operation) {
                     throw new IllegalOperationException("Division by zero is not allowed", e);
                 }
             }
-            default -> throw new IllegalOperationException(String.format("Operation '%s' does not exist", operation));
+            default -> throw new IllegalOperationException("Operation '" + operation + "' does not exist");
         }
 
-        return String.format("%d %s %d = %s", operand1, operation, operand2, result);
+        return String.valueOf(operand1) + " " + String.valueOf(operation) + " " + operand2 + " = " +  result;
     }
 }
diff --git a/exercises/concept/calculator-conundrum/src/test/java/CalculatorConundrumTest.java b/exercises/concept/calculator-conundrum/src/test/java/CalculatorConundrumTest.java
index 8481cb68a..e75144042 100644
--- a/exercises/concept/calculator-conundrum/src/test/java/CalculatorConundrumTest.java
+++ b/exercises/concept/calculator-conundrum/src/test/java/CalculatorConundrumTest.java
@@ -53,7 +53,7 @@ public void divisionWithLargeOperands() {
     @DisplayName("The calculate method throws IllegalOperationException when passing invalid operation")
     public void throwExceptionForUnknownOperation() {
         String invalidOperation = "**";
-        String expectedMessage = String.format("Operation '%s' does not exist", invalidOperation);
+        String expectedMessage = "Operation '" + invalidOperation + "' does not exist";
         assertThatExceptionOfType(IllegalOperationException.class)
                 .isThrownBy(() -> new CalculatorConundrum().calculate(3, 78, invalidOperation))
                 .withMessage(expectedMessage);
diff --git a/exercises/concept/captains-log/.meta/src/reference/java/CaptainsLog.java b/exercises/concept/captains-log/.meta/src/reference/java/CaptainsLog.java
index 28b2a773a..3e4d727fc 100644
--- a/exercises/concept/captains-log/.meta/src/reference/java/CaptainsLog.java
+++ b/exercises/concept/captains-log/.meta/src/reference/java/CaptainsLog.java
@@ -18,7 +18,9 @@ char randomPlanetClass() {
     String randomShipRegistryNumber() {
         var start = 1000;
         var end = 10000;
-        return String.format("NCC-%d", start + random.nextInt(end - start));
+
+
+        return "NCC-" + String.valueOf(start + random.nextInt(end - start));
     }
 
     double randomStardate() {
diff --git a/exercises/concept/logs-logs-logs/.meta/src/reference/java/LogLine.java b/exercises/concept/logs-logs-logs/.meta/src/reference/java/LogLine.java
index dceabeffa..c3ccfd4e6 100644
--- a/exercises/concept/logs-logs-logs/.meta/src/reference/java/LogLine.java
+++ b/exercises/concept/logs-logs-logs/.meta/src/reference/java/LogLine.java
@@ -21,6 +21,6 @@ public LogLevel getLogLevel() {
     }
 
     public String getOutputForShortLog() {
-        return String.format("%d:%s", this.level.getEncodedLevel(), this.message);
+        return String.valueOf(this.level.getEncodedLevel()) + ":" + this.message;
     }
 }